From 464d046b5a26cc6edfd8937041bc37bc0ef82328 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 17 Dec 2024 17:24:16 +0000
Subject: [PATCH 01/29] append-path spec behaviour for repeated /

---
 pkgs/anoia/init.fnl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pkgs/anoia/init.fnl b/pkgs/anoia/init.fnl
index 8fc65855..05ddd712 100644
--- a/pkgs/anoia/init.fnl
+++ b/pkgs/anoia/init.fnl
@@ -84,6 +84,8 @@
                  (false err) (expect (string.match err "path traversal"))))]
    (expect= (append-path "/tmp" "hello") "/tmp/hello")
    (expect= (append-path "/tmp/" "hello") "/tmp/hello")
+   (expect= (append-path "/tmp/" "///hello") "/tmp/hello")
+   (expect= (append-path "/tmp/" "///hello/../fish") "/tmp/fish")
    (traps "/tmp/" "../hello")
    (expect= (append-path "/tmp/" "hello/../goodbye") "/tmp/goodbye")
    (traps "/tmp/" "hello/../../goodbye"))

From 2e5a8a572eced1d5983e7ada3752fa2f8b1d564b Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 17 Dec 2024 17:24:40 +0000
Subject: [PATCH 02/29] tufted: more robust merge-pathname impl

---
 pkgs/tufted/tufted.fnl | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/pkgs/tufted/tufted.fnl b/pkgs/tufted/tufted.fnl
index d2f58c4e..275ddbd9 100644
--- a/pkgs/tufted/tufted.fnl
+++ b/pkgs/tufted/tufted.fnl
@@ -16,10 +16,18 @@
 
 (print (.. "TFTP serving from " options.base-directory))
 
-(fn merge-pathname [directory filename]
-  (if (directory:match "/$")
-      (.. directory  filename)
-      (.. directory "/" filename)))
+;; this is a copy of anoia append-path
+(fn  merge-pathname [dirname filename]
+  (let [base (or (string.match dirname "(.*)/$") dirname)
+        result []]
+    (each [component (string.gmatch filename "([^/]+)")]
+      (if (and (= component "..") (> (# result) 0))
+          (table.remove result)
+          (= component "..")
+          (error "path traversal attempt")
+          true
+          (table.insert result component)))
+    (.. base "/" (table.concat result "/"))))
 
 (->
  (tftp:listen

From 6e6b8790ebc164d1a543bf6fad92af05e000aad0 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 17 Dec 2024 17:24:52 +0000
Subject: [PATCH 03/29] think

---
 THOUGHTS.txt | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/THOUGHTS.txt b/THOUGHTS.txt
index dfcda44f..6c7a467f 100644
--- a/THOUGHTS.txt
+++ b/THOUGHTS.txt
@@ -6539,3 +6539,32 @@ using a Makefile
 
 idea 2: when a configuration contains levitate, something similar
 but necessarily more "manual" to do the analogous thing
+
+
+Sun Dec 15 18:55:55 GMT 2024
+
+Where we left off with this, rotuer was crashing randomly or failing
+to boot every time we tried to add log shipping, which is not very
+ideal. I started doing something with logging to /dev/pmsg0
+(CONFIG_PSTORE_PMSG) but I think (there seems not to be anything
+written down :-( ) that the gl-ar750 kernel needs it added to kconfig and device tree
+
+https://wiki.postmarketos.org/wiki/User:Knuxify/Enabling_pstore_and_ramoops
+
+we could add a new hardware.dts.dtsi = [] option so that any module
+could add a new chunk of dts. (Ideally we'd call it `includes`
+but that conflicts with the existing use of `includes` to specify
+search path. Maybe rename?)
+
+would we ever use it except in a hardware device definition?
+(Or user config?) I guess if we were consistent with names
+then we could set up nodes in the device file with status="disabled"
+and enable them in the module, except that dt doesn't consistently
+use status and in fact there isn't one for reserved-memory
+
+we could use global config to enable pstore_msg and check it in
+the device module to enable the needed hw support
+
+
+
+00PA727 00PA735

From 44caefcd3bab54c69012d872c681ae782ef3c043 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 17 Dec 2024 17:34:04 +0000
Subject: [PATCH 04/29] rename config.hardware.dts.includes -> includePaths

(1) it's a better name
(2) I want to use `includes` to specify dtsi files
---
 NEWS                               | 4 ++++
 devices/belkin-rt3200/default.nix  | 2 +-
 devices/gl-ar750/default.nix       | 2 +-
 devices/gl-mt300a/default.nix      | 2 +-
 devices/gl-mt300n-v2/default.nix   | 2 +-
 devices/qemu/default.nix           | 2 +-
 devices/tp-archer-ax23/default.nix | 2 +-
 devices/turris-omnia/default.nix   | 2 +-
 devices/zyxel-nwa50ax/default.nix  | 6 +++---
 modules/hardware.nix               | 2 +-
 modules/outputs.nix                | 2 +-
 11 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/NEWS b/NEWS
index 9766bd85..6aaca646 100644
--- a/NEWS
+++ b/NEWS
@@ -132,4 +132,8 @@ and then run the generated `install.sh` script
 
     result/install.sh root@192.168.8.1
 
+2024-12-16
 
+config option rename: config.hardware.dts.includes is now
+hardware.dts.includePaths, which is a better name and  also
+means I can use hardware.dts.includes for a different purpose
\ No newline at end of file
diff --git a/devices/belkin-rt3200/default.nix b/devices/belkin-rt3200/default.nix
index edd6f068..4a6fd0ec 100644
--- a/devices/belkin-rt3200/default.nix
+++ b/devices/belkin-rt3200/default.nix
@@ -197,7 +197,7 @@
         rootDevice = "ubi0:liminix";
         dts = {
           src = "${openwrt.src}/target/linux/mediatek/dts/mt7622-linksys-e8450-ubi.dts";
-          includes =  [
+          includePaths =  [
             "${openwrt.src}/target/linux/mediatek/dts"
             "${config.system.outputs.kernel.modulesupport}/arch/arm64/boot/dts/mediatek/"
           ];
diff --git a/devices/gl-ar750/default.nix b/devices/gl-ar750/default.nix
index dd58f1d2..73c0e712 100644
--- a/devices/gl-ar750/default.nix
+++ b/devices/gl-ar750/default.nix
@@ -116,7 +116,7 @@
         rootDevice = "/dev/mtdblock5";
         dts = {
           src = "${openwrt.src}/target/linux/ath79/dts/qca9531_glinet_gl-ar750.dts";
-          includes =  [
+          includePaths =  [
             "${openwrt.src}/target/linux/ath79/dts"
           ];
         };
diff --git a/devices/gl-mt300a/default.nix b/devices/gl-mt300a/default.nix
index e89723d6..6659951f 100644
--- a/devices/gl-mt300a/default.nix
+++ b/devices/gl-mt300a/default.nix
@@ -81,7 +81,7 @@
 
         dts = {
           src = "${openwrt.src}/target/linux/ramips/dts/mt7620a_glinet_gl-mt300a.dts";
-          includes = [
+          includePaths = [
             "${openwrt.src}/target/linux/ramips/dts"
           ];
         };
diff --git a/devices/gl-mt300n-v2/default.nix b/devices/gl-mt300n-v2/default.nix
index da3fbbab..ae12317d 100644
--- a/devices/gl-mt300n-v2/default.nix
+++ b/devices/gl-mt300n-v2/default.nix
@@ -78,7 +78,7 @@
 
         dts = {
           src = "${openwrt.src}/target/linux/ramips/dts/mt7628an_glinet_gl-mt300n-v2.dts";
-          includes = [
+          includePaths = [
             "${openwrt.src}/target/linux/ramips/dts"
           ];
         };
diff --git a/devices/qemu/default.nix b/devices/qemu/default.nix
index b0d74721..91b80506 100644
--- a/devices/qemu/default.nix
+++ b/devices/qemu/default.nix
@@ -66,7 +66,7 @@
         # *correct* but it does at least boot
         dts = lib.mkForce {
           src = "${config.system.outputs.kernel.modulesupport}/arch/mips/boot/dts/mti/malta.dts";
-          includes =  [
+          includePaths =  [
             "${config.system.outputs.kernel.modulesupport}/arch/mips/boot/dts/"
           ];
         };
diff --git a/devices/tp-archer-ax23/default.nix b/devices/tp-archer-ax23/default.nix
index 93e289fb..64eff0fd 100644
--- a/devices/tp-archer-ax23/default.nix
+++ b/devices/tp-archer-ax23/default.nix
@@ -410,7 +410,7 @@
           rootDevice = "/dev/mtdblock3";
           dts = {
             src = "${openwrt.src}/target/linux/ramips/dts/mt7621_tplink_archer-ax23-v1.dts";
-            includes =  [
+            includePaths =  [
               "${openwrt.src}/target/linux/ramips/dts"
               "${config.system.outputs.kernel.modulesupport}/arch/arm64/boot/dts/mediatek/"
             ];
diff --git a/devices/turris-omnia/default.nix b/devices/turris-omnia/default.nix
index 3ea83ec1..02914dd2 100644
--- a/devices/turris-omnia/default.nix
+++ b/devices/turris-omnia/default.nix
@@ -348,7 +348,7 @@
 
           dts = {
             src = "${config.system.outputs.kernel.modulesupport}/arch/arm/boot/dts/marvell/armada-385-turris-omnia.dts";
-            includes =  [
+            includePaths =  [
               "${config.system.outputs.kernel.modulesupport}/arch/arm/boot/dts/marvell/"
             ];
           };
diff --git a/devices/zyxel-nwa50ax/default.nix b/devices/zyxel-nwa50ax/default.nix
index 920acac4..9c9b9d9c 100644
--- a/devices/zyxel-nwa50ax/default.nix
+++ b/devices/zyxel-nwa50ax/default.nix
@@ -124,7 +124,7 @@
         hash = "sha256-ifriAjWzFACrxVWCANZpUaEZgB/0pdbhnTVQytx6ddg=";
       };
     in {
-      imports = [ 
+      imports = [
         # We include it to ensure the bridge functionality
         # is available on the target kernel.
         ../../modules/bridge
@@ -184,7 +184,7 @@
           # Actually, this is not what we want.
           # This DTS is insufficient.
           src = ./mt7621_zyxel_nwa50ax.dtsi;
-          includes = [
+          includePaths = [
             # Here's one weird trick to make `ubi` detection
             # out of the box.
             # We will write ubi on /dev/firmware_a:rootfs location
@@ -233,7 +233,7 @@
       services.zyxel-dual-image = config.boot.zyxel-dual-image.build {
         ensureActiveImage = "primary";
         # TODO: use mtd names rather…
-        # primary and secondary are always /dev/mtd3 by virtue of the 
+        # primary and secondary are always /dev/mtd3 by virtue of the
         # dtb being not too wrong…
         # TODO: remove this hack.
         primaryMtdPartition = "/dev/mtd3";
diff --git a/modules/hardware.nix b/modules/hardware.nix
index 48bdf40f..27c4e97d 100644
--- a/modules/hardware.nix
+++ b/modules/hardware.nix
@@ -24,7 +24,7 @@ in
             only for QEMU.
           '';
         };
-        includes = mkOption {
+        includePaths = mkOption {
           default = [ ];
           description = "List of directories to search for DTS includes (.dtsi files)";
           type = types.listOf types.path;
diff --git a/modules/outputs.nix b/modules/outputs.nix
index 16742a52..5ab12b76 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -105,7 +105,7 @@ in
       dtb = liminix.builders.dtb {
         inherit (config.boot) commandLine;
         dts = config.hardware.dts.src;
-        includes = config.hardware.dts.includes ++ [
+        includes = config.hardware.dts.includePaths ++ [
           "${o.kernel.headers}/include"
         ];
       };

From b52133a28bfc8bd7e264a9a3b9ea0cce7e64224a Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 17 Dec 2024 20:36:14 +0000
Subject: [PATCH 05/29] add hardware.dts.includes option

---
 NEWS                 | 11 ++++++++---
 modules/hardware.nix |  5 +++++
 modules/outputs.nix  |  2 +-
 pkgs/kernel/dtb.nix  | 12 ++++++++++--
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/NEWS b/NEWS
index 6aaca646..11cd3069 100644
--- a/NEWS
+++ b/NEWS
@@ -134,6 +134,11 @@ and then run the generated `install.sh` script
 
 2024-12-16
 
-config option rename: config.hardware.dts.includes is now
-hardware.dts.includePaths, which is a better name and  also
-means I can use hardware.dts.includes for a different purpose
\ No newline at end of file
+Config options changed: if you had set config.hardware.dts.includes
+(maybe in an out-of-tree device port) to specify the search paths
+in which dtc finds include files, you will need to change this to 
+hardware.dts.includePaths.
+
+The "new" hardware.dts.includes option is now for dtsi files which
+should be merged into the device tree.
+
diff --git a/modules/hardware.nix b/modules/hardware.nix
index 27c4e97d..056cd04f 100644
--- a/modules/hardware.nix
+++ b/modules/hardware.nix
@@ -29,6 +29,11 @@ in
           description = "List of directories to search for DTS includes (.dtsi files)";
           type = types.listOf types.path;
         };
+        includes = mkOption {
+          default = [ ];
+          description = "\"dtsi\" fragments to include in the generated device tree";
+          type = types.listOf types.path;
+        };
       };
       defaultOutput = mkOption {
         description = "\"Default\" output: what gets built for this device when outputs.default is requested. Typically this is \"mtdimage\" or \"vmroot\"";
diff --git a/modules/outputs.nix b/modules/outputs.nix
index 5ab12b76..84f6f457 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -104,7 +104,7 @@ in
     system.outputs = rec {
       dtb = liminix.builders.dtb {
         inherit (config.boot) commandLine;
-        dts = config.hardware.dts.src;
+        dts = config.hardware.dts.includes ++ [config.hardware.dts.src];
         includes = config.hardware.dts.includePaths ++ [
           "${o.kernel.headers}/include"
         ];
diff --git a/pkgs/kernel/dtb.nix b/pkgs/kernel/dtb.nix
index f971cece..505c4a6e 100644
--- a/pkgs/kernel/dtb.nix
+++ b/pkgs/kernel/dtb.nix
@@ -2,6 +2,8 @@
   stdenv
 , dtc
 , lib
+, runCommand
+, writeText
 }:
 { dts
 , includes
@@ -10,14 +12,20 @@
   cppDtSearchFlags = builtins.concatStringsSep " " (map (f: "-I${f}") includes);
   dtcSearchFlags = builtins.concatStringsSep " " (map (f: "-i${f}") includes);
   cmdline = lib.concatStringsSep " " commandLine;
+  chosen = writeText "chosen.dtsi" "/{ chosen { bootargs = ${builtins.toJSON cmdline}; }; };";
+  combined = writeText "combined-dts-fragments"
+    (lib.concatStrings
+      (builtins.map
+        (f: "#include \"${f}\"\n")
+        (dts ++ [ chosen ])));
 in stdenv.mkDerivation {
   name = "dtb";
   phases = [ "buildPhase" ];
   nativeBuildInputs = [ dtc ];
   buildPhase = ''
-    ${stdenv.cc.targetPrefix}cpp -nostdinc -x assembler-with-cpp ${cppDtSearchFlags} -undef -D__DTS__  -o dtb.tmp ${dts}
-    echo '/{ chosen { bootargs = ${builtins.toJSON cmdline}; }; };'  >> dtb.tmp
+    ${stdenv.cc.targetPrefix}cpp -nostdinc -x assembler-with-cpp ${cppDtSearchFlags} -undef -D__DTS__  -o dtb.tmp ${combined}
     dtc ${dtcSearchFlags} -I dts  -O dtb -o $out dtb.tmp
+    # dtc -I dtb  -O dts  $out
     test -e $out
   '';
 }

From 81f5550bf0c85dc8b32ac9539cd4144ae4bd2227 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 17 Dec 2024 23:24:31 +0000
Subject: [PATCH 06/29] config.logging.persistent enables /dev/pmsg0

- whatever's written to /dev/pmsg0 appears as
/sys/fs/pstore/pmsg-ramoops-0 after reboot

- only works on devices with the relevant device tree
support (gl-ar750 and whatever has it by default)

- nothing in the system is actually writing this file yet

- or reading it at boot time, for that matter
---
 devices/gl-ar750/default.nix         |  6 +++++-
 devices/gl-ar750/pstore-ramoops.dtsi | 10 ++++++++++
 modules/outputs.nix                  |  2 +-
 modules/s6/default.nix               |  8 ++++++++
 4 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 devices/gl-ar750/pstore-ramoops.dtsi

diff --git a/devices/gl-ar750/default.nix b/devices/gl-ar750/default.nix
index 73c0e712..7be4c904 100644
--- a/devices/gl-ar750/default.nix
+++ b/devices/gl-ar750/default.nix
@@ -52,8 +52,9 @@
 
   '';
 
-  module = {pkgs, config, lim, ... }:
+  module = {pkgs, config, lim, lib, ... }:
     let
+      inherit (lib) mkIf;
       openwrt = pkgs.openwrt;
       firmwareBlobs = pkgs.pkgsBuildBuild.fetchFromGitHub {
         owner = "kvalo";
@@ -119,6 +120,9 @@
           includePaths =  [
             "${openwrt.src}/target/linux/ath79/dts"
           ];
+          includes = mkIf config.logging.persistent.enable [
+            ./pstore-ramoops.dtsi
+          ];
         };
 
         networkInterfaces =
diff --git a/devices/gl-ar750/pstore-ramoops.dtsi b/devices/gl-ar750/pstore-ramoops.dtsi
new file mode 100644
index 00000000..bd4f922f
--- /dev/null
+++ b/devices/gl-ar750/pstore-ramoops.dtsi
@@ -0,0 +1,10 @@
+/ {
+reserved-memory {
+		ramoops@03f00000 {
+			compatible = "ramoops";
+			reg = <0x03f00000 0x10000>;
+			record-size = <0x1000>;
+			pmsg-size = <0x1000>;
+		};
+	};
+};
diff --git a/modules/outputs.nix b/modules/outputs.nix
index 84f6f457..2cf4d8b4 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -104,7 +104,7 @@ in
     system.outputs = rec {
       dtb = liminix.builders.dtb {
         inherit (config.boot) commandLine;
-        dts = config.hardware.dts.includes ++ [config.hardware.dts.src];
+        dts = [config.hardware.dts.src] ++ config.hardware.dts.includes;
         includes = config.hardware.dts.includePaths ++ [
           "${o.kernel.headers}/include"
         ];
diff --git a/modules/s6/default.nix b/modules/s6/default.nix
index 1a98f41d..f23edece 100644
--- a/modules/s6/default.nix
+++ b/modules/s6/default.nix
@@ -212,6 +212,9 @@ let
 in {
   options = {
     logging = {
+      persistent = {
+        enable = mkEnableOption "store logs across reboots";
+      };
       shipping = {
         enable = mkEnableOption "unix socket for log shipping";
         socket = mkOption {
@@ -263,6 +266,11 @@ in {
     )];
 
   config = {
+    kernel.config = mkIf config.logging.persistent.enable {
+      PSTORE = "y";
+      PSTORE_PMSG = "y";
+      PSTORE_RAM = "y";
+    };
     filesystem = dir {
       etc = dir {
         s6-rc = dir {

From 77cd4492b2b1427cbb8c918add7f3e3694d354ba Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 17 Dec 2024 23:26:56 +0000
Subject: [PATCH 07/29] unbreak nix-shell

---
 shell.nix | 1 -
 1 file changed, 1 deletion(-)

diff --git a/shell.nix b/shell.nix
index 02b7cd8c..353a52b3 100644
--- a/shell.nix
+++ b/shell.nix
@@ -3,7 +3,6 @@ let
   liminix = (import ./default.nix {
     device = (import ./devices/qemu);
     liminix-config = ./vanilla-configuration.nix;
-    inherit nixpkgs;
   });
   here = builtins.toString ./.;
 in liminix.buildEnv.overrideAttrs (o: {

From ffaca615baf33b6df154ebdf94e49a98e484e29c Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Wed, 18 Dec 2024 21:11:58 +0000
Subject: [PATCH 08/29] copy logs to /dev/pmsg0 when ogging.persistent.enabled

---
 modules/s6/default.nix | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/modules/s6/default.nix b/modules/s6/default.nix
index f23edece..53d79680 100644
--- a/modules/s6/default.nix
+++ b/modules/s6/default.nix
@@ -7,10 +7,27 @@ let
     s6-linux-init
     stdenvNoCC;
   inherit (lib.lists) unique concatMap;
+  inherit (lib) concatStrings;
+  inherit (builtins) map;
   inherit (pkgs.pseudofile) dir symlink;
   inherit (pkgs.liminix.services) oneshot bundle longrun;
   inherit (lib) mkIf mkEnableOption mkOption types;
   cfg = config.logging;
+
+  logger =
+    let pipecmds =
+          ["${s6}/bin/s6-log -bpd3 -- ${cfg.script} 1"] ++
+          (lib.optional cfg.persistent.enable
+            "/bin/tee /dev/pmsg0") ++
+          (lib.optional cfg.shipping.enable
+            "${pkgs.logshipper}/bin/logtap ${cfg.shipping.socket} logshipper-socket-event");
+    in ''
+      #!${execline}/bin/execlineb -P
+      ${execline}/bin/redirfd -w 1 /dev/null
+      ${execline}/bin/redirfd -rnb 0 fifo
+      ${concatStrings (map (l: "pipeline { ${l} }\n") pipecmds)}
+      ${s6}/bin/s6-log -- ${cfg.directory}
+    '';
   s6-rc-db =
     let
       # In the default bundle we need to have all the services
@@ -106,21 +123,7 @@ let
         mode = "0600";
       };
       notification-fd = { file = "3"; };
-      run = {
-        file = ''
-              #!${execline}/bin/execlineb -P
-              ${execline}/bin/redirfd -w 1 /dev/null
-              ${execline}/bin/redirfd -rnb 0 fifo
-              ${if cfg.shipping.enable then ''
-                pipeline { ${s6}/bin/s6-log -bpd3 -- ${cfg.script} 1 }
-                pipeline { ${pkgs.logshipper}/bin/logtap ${cfg.shipping.socket} logshipper-socket-event }
-                ${s6}/bin/s6-log -- ${cfg.directory}
-              '' else ''
-                ${s6}/bin/s6-log -bpd3 -- ${cfg.script} ${cfg.directory}
-              ''}
-          '';
-        mode = "0755";
-      };
+      run = { file = logger; mode = "0755"; };
     };
     getty = dir {
       run = {

From 3357d21d7fb53237f1114d90623a9304b43306de Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Wed, 18 Dec 2024 21:16:49 +0000
Subject: [PATCH 09/29] enlarge pmsg buffer to full size of ramoops region

4k was a piddly amount and we weren't using the rest of it for
anything else
---
 devices/gl-ar750/pstore-ramoops.dtsi | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/devices/gl-ar750/pstore-ramoops.dtsi b/devices/gl-ar750/pstore-ramoops.dtsi
index bd4f922f..b81801d1 100644
--- a/devices/gl-ar750/pstore-ramoops.dtsi
+++ b/devices/gl-ar750/pstore-ramoops.dtsi
@@ -3,8 +3,7 @@ reserved-memory {
 		ramoops@03f00000 {
 			compatible = "ramoops";
 			reg = <0x03f00000 0x10000>;
-			record-size = <0x1000>;
-			pmsg-size = <0x1000>;
+			pmsg-size = <0x10000>;
 		};
 	};
 };

From ba5e4704a05cadfe4ccb478e06106d7e6240e53f Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Wed, 18 Dec 2024 23:08:28 +0000
Subject: [PATCH 10/29] add short note about persistent logs

---
 doc/admin.rst | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/doc/admin.rst b/doc/admin.rst
index 69d28720..3ea30f60 100644
--- a/doc/admin.rst
+++ b/doc/admin.rst
@@ -131,6 +131,26 @@ human-readable format, use :command:`s6-tai64nlocal`.
   1970-01-02 21:51:48.832588765 wan.link.pppoe sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x667a9594> <pcomp> <accom
   p>]
 
+Log persistence
+---------------
+
+Logs written to :file:`/run/log/` will not survive a reboot or crash,
+as it is an ephemeral filesystem.
+
+On supported hardware you can enable logging to `pstore
+<https://www.kernel.org/doc/Documentation/ABI/testing/pstore>` which
+means the most recent log messages will be preserved on reboot.
+Set the config option ``logging.persistent.enable = true``, log messages will be written to :file:/dev/pmsg0.  After rebooting,
+
+.. code-block:: console
+
+    # mount -t pstore pstore /sys/fs/pstore/
+    # ls -l /sys/fs/pstore/
+    -r--r--r--    1     43071 pmsg-ramoops-0
+    # cat /sys/fs/pstore/pmsg-ramoops-0
+    @40000000000000282c997d29 mydevice klogd <6>[   30.793756] int: port 2(wlan0) entered blocking state
+    [log messages from before the reboot follow]
+
 
 
 Updating an installed system (JFFS2)

From f9b4f0bc9c36802f543f1b1f7e58f98de20a289d Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 19 Dec 2024 14:32:44 +0000
Subject: [PATCH 11/29] move modules/squashfs.nix into outputs/

---
 modules/all-modules.nix            | 1 -
 modules/outputs.nix                | 2 +-
 modules/{ => outputs}/squashfs.nix | 0
 tests/jffs2/configuration.nix      | 2 +-
 4 files changed, 2 insertions(+), 3 deletions(-)
 rename modules/{ => outputs}/squashfs.nix (100%)

diff --git a/modules/all-modules.nix b/modules/all-modules.nix
index 1e4df4e3..982e4f31 100644
--- a/modules/all-modules.nix
+++ b/modules/all-modules.nix
@@ -30,7 +30,6 @@
    ./outputs/vmroot.nix
    ./ppp
    ./ramdisk.nix
-   ./squashfs.nix
    ./ssh
    ./users.nix
    ./vlan
diff --git a/modules/outputs.nix b/modules/outputs.nix
index 2cf4d8b4..e0204eca 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -11,7 +11,7 @@ let
 in
 {
   imports = [
-    ./squashfs.nix
+    ./outputs/squashfs.nix
     ./outputs/vmroot.nix
     ./outputs/extlinux.nix
   ];
diff --git a/modules/squashfs.nix b/modules/outputs/squashfs.nix
similarity index 100%
rename from modules/squashfs.nix
rename to modules/outputs/squashfs.nix
diff --git a/tests/jffs2/configuration.nix b/tests/jffs2/configuration.nix
index 11d1f3e5..010aa15d 100644
--- a/tests/jffs2/configuration.nix
+++ b/tests/jffs2/configuration.nix
@@ -4,7 +4,7 @@ let
 in {
   imports = [
     ../../vanilla-configuration.nix
-    ../../modules/squashfs.nix
+    ../../modules/outputs/squashfs.nix
     ../../modules/outputs/jffs2.nix
   ];
   config.rootfsType = "jffs2";

From 56c667cfd5d862df2bdb240e86e13f3e8b73ada6 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 19 Dec 2024 20:55:10 +0000
Subject: [PATCH 12/29] extract systemConfiguration into its own output module

---
 modules/outputs/initramfs.nix            | 11 +---------
 modules/outputs/system-configuration.nix | 28 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 10 deletions(-)
 create mode 100644 modules/outputs/system-configuration.nix

diff --git a/modules/outputs/initramfs.nix b/modules/outputs/initramfs.nix
index 6599429d..37ff60c0 100644
--- a/modules/outputs/initramfs.nix
+++ b/modules/outputs/initramfs.nix
@@ -9,6 +9,7 @@ let
   inherit (pkgs) runCommand;
 in
 {
+  imports = [ ./system-configuration.nix ];
   options = {
     boot.initramfs = {
       enable = mkEnableOption "initramfs";
@@ -22,14 +23,6 @@ in
           filesystem
         '';
       };
-      systemConfiguration = mkOption {
-        type = types.package;
-        description = ''
-          pkgs.systemconfig for the configured filesystem,
-          contains 'activate' and 'init' commands
-        '';
-        internal = true;
-      };
     };
   };
   config = mkIf config.boot.initramfs.enable {
@@ -53,8 +46,6 @@ in
           file /init ${pkgs.preinit}/bin/preinit 0755 0 0
           SPECIALS
         '';
-      systemConfiguration =
-        pkgs.systemconfig config.filesystem.contents;
     };
   };
 }
diff --git a/modules/outputs/system-configuration.nix b/modules/outputs/system-configuration.nix
new file mode 100644
index 00000000..90f87ac0
--- /dev/null
+++ b/modules/outputs/system-configuration.nix
@@ -0,0 +1,28 @@
+{
+  config
+, pkgs
+, lib
+, ...
+}:
+let
+  inherit (lib) mkEnableOption mkOption mkIf types;
+  inherit (pkgs) runCommand;
+in
+{
+  options = {
+    system.outputs = {
+      systemConfiguration = mkOption {
+        type = types.package;
+        description = ''
+          pkgs.systemconfig for the configured filesystem,
+          contains 'activate' and 'init' commands
+        '';
+        internal = true;
+      };
+    };
+  };
+  config = {
+    system.outputs.systemConfiguration =
+        pkgs.systemconfig config.filesystem.contents;
+  };
+}

From 420552ce98600e6b3307c93ab82b1d8c2ca60ad4 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 19 Dec 2024 20:56:05 +0000
Subject: [PATCH 13/29] add omnia to ci

---
 ci.nix                           | 1 +
 devices/turris-omnia/default.nix | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/ci.nix b/ci.nix
index 1baecaee..d86fd895 100644
--- a/ci.nix
+++ b/ci.nix
@@ -12,6 +12,7 @@ let
     "qemu-armv7l"
     "tp-archer-ax23"
     "zyxel-nwa50ax"
+    "turris-omnia"
   ];
   vanilla = ./vanilla-configuration.nix;
   for-device = name:
diff --git a/devices/turris-omnia/default.nix b/devices/turris-omnia/default.nix
index 02914dd2..5a93c032 100644
--- a/devices/turris-omnia/default.nix
+++ b/devices/turris-omnia/default.nix
@@ -173,6 +173,7 @@
         ../../modules/outputs/tftpboot.nix
         ../../modules/outputs/mbrimage.nix
         ../../modules/outputs/extlinux.nix
+        ../../modules/outputs/system-configuration.nix
       ];
 
       config = {
@@ -341,7 +342,7 @@
             targets = ["ath9k" "ath10k_pci"];
           };
         in {
-          defaultOutput = "mtdimage";
+          defaultOutput = "systemConfiguration";
           loadAddress = lim.parseInt "0x00800000"; # "0x00008000";
           entryPoint = lim.parseInt "0x00800000"; # "0x00008000";
           rootDevice = "/dev/mmcblk0p1";

From 1af9a39db10862fc79b37d564be059027c4171fc Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 19 Dec 2024 20:59:52 +0000
Subject: [PATCH 14/29] omnia: delete pstore config we're probably not using

---
 devices/turris-omnia/default.nix | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/devices/turris-omnia/default.nix b/devices/turris-omnia/default.nix
index 5a93c032..7845cb01 100644
--- a/devices/turris-omnia/default.nix
+++ b/devices/turris-omnia/default.nix
@@ -225,11 +225,6 @@
             # WARNING: unmet direct dependencies detected for ARCH_WANT_LIBATA_LEDS
             ATA = "y";
 
-            PSTORE = "y";
-            PSTORE_RAM = "y";
-            PSTORE_CONSOLE = "y";
-#            PSTORE_DEFLATE_COMPRESS = "n";
-
             BLOCK = "y";
             MMC="y";
             PWRSEQ_EMMC="y";        # ???

From 172f3686338df3fd432d03f3f8dfd202663f577f Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 19 Dec 2024 21:59:04 +0000
Subject: [PATCH 15/29] fix markup

---
 doc/admin.rst | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/doc/admin.rst b/doc/admin.rst
index 3ea30f60..78e0c0d7 100644
--- a/doc/admin.rst
+++ b/doc/admin.rst
@@ -138,9 +138,15 @@ Logs written to :file:`/run/log/` will not survive a reboot or crash,
 as it is an ephemeral filesystem.
 
 On supported hardware you can enable logging to `pstore
-<https://www.kernel.org/doc/Documentation/ABI/testing/pstore>` which
-means the most recent log messages will be preserved on reboot.
-Set the config option ``logging.persistent.enable = true``, log messages will be written to :file:/dev/pmsg0.  After rebooting,
+<https://www.kernel.org/doc/Documentation/ABI/testing/pstore>`_ which
+means the most recent log messages will be preserved on reboot.  Set
+the config option ``logging.persistent.enable = true`` to log messages
+to :file:`/dev/pmsg0` as well as to the regular log. This is a
+circular buffer, so when it fills up newer messages will overwrite the
+oldest messages.
+
+To check the previous messages after a (planned or forced) reboot,
+you need to mooun the pstore filesystem.
 
 .. code-block:: console
 

From 812e35b7b9e732f5d6b507063896631bc5ad29bf Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 19 Dec 2024 22:28:30 +0000
Subject: [PATCH 16/29] systemconfig: improve filenames/pathnames

no more make-stuff
---
 pkgs/systemconfig/default.nix | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/pkgs/systemconfig/default.nix b/pkgs/systemconfig/default.nix
index 1fe2c4ac..4192667a 100644
--- a/pkgs/systemconfig/default.nix
+++ b/pkgs/systemconfig/default.nix
@@ -56,31 +56,31 @@ let
                     else "";
           in "unlink(${qpathname}); ${cmd} ${chown}";
     in mapAttrsToList (makeFile prefix) attrset;
-  activateScript = attrset: writeText "makedevs.c" ''
-    #include "defs.h"
-    int main(int argc, char* argv[]) {
-      chdir(argv[1]);
-      ${(builtins.concatStringsSep "\n" (visit "." attrset))}
-    }
-  '';
 in attrset:
-  let makedevs = activateScript attrset;
+  let
+    activateScript = writeText "activate.c" ''
+      #include "defs.h"
+      int main(int argc, char* argv[]) {
+        chdir(argv[1]);
+        ${(builtins.concatStringsSep "\n" (visit "." attrset))}
+      }
+    '';
   in stdenv.mkDerivation {
-    name="make-stuff";
+    name="system-configuration";
     src = ./.;
 
     CFLAGS = "-Os";
     LDFLAGS  = "-static -Xlinker -static";
 
     postConfigure = ''
-      cp ${makedevs} makedevs.c
+      cp ${activateScript} activate.c
     '';
-    makeFlags = ["makedevs"];
+    makeFlags = ["activate"];
     installPhase = ''
-      closure=${closureInfo { rootPaths = [ makedevs ]; }}
+      closure=${closureInfo { rootPaths = [ activateScript ]; }}
       mkdir -p $out/bin $out/etc
       cp $closure/store-paths $out/etc/nix-store-paths
-      $STRIP --remove-section=.note  --remove-section=.comment --strip-all makedevs -o $out/bin/activate
+      $STRIP --remove-section=.note  --remove-section=.comment --strip-all activate -o $out/bin/activate
       ln -s ${s6-init-bin}/bin/init $out/bin/init
       cp -p ${writeFennel "restart-services" {} ./restart-services.fnl} $out/bin/restart-services
       # obfuscate the store path of min-copy-closure so that the output

From f60b74f415f5435adf6f34158889f12465d501a6 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Fri, 20 Dec 2024 00:05:07 +0000
Subject: [PATCH 17/29] add a new updater output

this is so that we don't have to obfuscate store paths in
systemConfiguration to avoid dragging in build system
deps.

breaking-ish change to workflows, docs updated
---
 NEWS                                          | 10 +++
 devices/turris-omnia/default.nix              |  4 +-
 doc/admin.rst                                 | 67 +++++++++----------
 modules/outputs.nix                           |  1 +
 modules/outputs/updater/default.nix           | 36 ++++++++++
 .../outputs/updater/update.sh                 | 14 ++--
 pkgs/systemconfig/default.nix                 |  5 --
 7 files changed, 86 insertions(+), 51 deletions(-)
 create mode 100644 modules/outputs/updater/default.nix
 rename pkgs/systemconfig/build-system-install.sh => modules/outputs/updater/update.sh (65%)

diff --git a/NEWS b/NEWS
index 11cd3069..b8ad2ffe 100644
--- a/NEWS
+++ b/NEWS
@@ -142,3 +142,13 @@ hardware.dts.includePaths.
 The "new" hardware.dts.includes option is now for dtsi files which
 should be merged into the device tree.
 
+2024-12-19
+
+Incremental updates changed again (but not massively). From hereon in,
+the preferred way to do an incremental update on an installed device
+with a writable filesystem is to build the updater output
+
+    nix-build  -I liminix-config=hosts/myhost.nix --argstr deviceName turris-omnia -A outputs.updater
+
+and then run the generated `update.sh` script. See 
+https://www.liminix.org/doc/admin.html#updating-an-installed-system
\ No newline at end of file
diff --git a/devices/turris-omnia/default.nix b/devices/turris-omnia/default.nix
index 7845cb01..bcf50f2d 100644
--- a/devices/turris-omnia/default.nix
+++ b/devices/turris-omnia/default.nix
@@ -172,8 +172,6 @@
         ../../modules/arch/arm.nix
         ../../modules/outputs/tftpboot.nix
         ../../modules/outputs/mbrimage.nix
-        ../../modules/outputs/extlinux.nix
-        ../../modules/outputs/system-configuration.nix
       ];
 
       config = {
@@ -337,7 +335,7 @@
             targets = ["ath9k" "ath10k_pci"];
           };
         in {
-          defaultOutput = "systemConfiguration";
+          defaultOutput = "updater";
           loadAddress = lim.parseInt "0x00800000"; # "0x00008000";
           entryPoint = lim.parseInt "0x00800000"; # "0x00008000";
           rootDevice = "/dev/mmcblk0p1";
diff --git a/doc/admin.rst b/doc/admin.rst
index 78e0c0d7..9a128818 100644
--- a/doc/admin.rst
+++ b/doc/admin.rst
@@ -159,48 +159,26 @@ you need to mooun the pstore filesystem.
 
 
 
-Updating an installed system (JFFS2)
-************************************
+Updating an installed system
+****************************
 
+If your system has a writable root filesystem (JFFS2, btrfs etc -
+anything but squashfs), we have mechanisms for in-places updates
+analogous to :command:`nixos-rebuild`, but the operation is a bit
+different because it expects to run on a build machine and then copy
+to the host device using :command:`ssh`.
 
-Adding packages
-===============
-
-If your device is running a JFFS2 root filesystem, you can build
-extra packages for it on your build system and copy them to the
-device: any package in Nixpkgs or in the Liminix overlay is available
-with the ``pkgs`` prefix:
-
-.. code-block:: console
-
-    nix-build -I liminix-config=./my-configuration.nix \
-     --arg device "import ./devices/mydevice" -A pkgs.tcpdump
-
-    nix-shell -p min-copy-closure root@the-device result/
-
-Note that this only copies the package to the device: it doesn't update
-any profile to add it to ``$PATH``
-
-
-.. _rebuilding the system:
-
-Rebuilding the system
-=====================
-
-Liminix has a mechanism for in-place updates of a running system which
-is analogous to :command:`nixos-rebuild`, but its operation is a
-bit different because it expects to run on a build machine and then
-copy to the host device. To use this, build the `outputs.systemConfiguration`
-target and then run the :command:`result/install.sh` script it generates.
+To use this, build the ``outputs.updater``
+target and then run the :command:`update.sh` script it generates.
 
 .. code-block:: console
 
     nix-build -I liminix-config=./my-configuration.nix \
        --arg device "import ./devices/mydevice" \
-       -A outputs.systemConfiguration
-    ./result/install.sh root@the-device 
+       -A outputs.updater
+    ./result/bin/update.sh root@the-device 
 
-The install script uses min-copy-closure to copy new or changed
+The update script uses min-copy-closure to copy new or changed
 packages to the device, then (perhaps) reboots it. The reboot
 behaviour can be affected by flags:
 
@@ -213,7 +191,6 @@ behaviour can be affected by flags:
   the services that have updated store paths (and anything that
   depends on them), but will not affect services that haven't changed.
 
-
 It doesn't delete old packages automatically: to do that run
 :command:`min-collect-garbage`, which will delete any packages not in
 the current system closure. Note that Liminix does not have the NixOS
@@ -233,6 +210,26 @@ Caveats
 
 .. _levitate:  
 
+Adding packages
+===============
+
+If you simply wish to add a package without any change to services,
+you can call :command:`min-copy-closure` directly to install
+any package in Nixpkgs or in the Liminix overlay
+
+.. code-block:: console
+
+    nix-build -I liminix-config=./my-configuration.nix \
+     --arg device "import ./devices/mydevice" -A pkgs.tcpdump
+
+    nix-shell -p min-copy-closure root@the-device result/
+
+Note that this only copies the package and its dependencies to the
+device: it doesn't update any profile to add it to ``$PATH``
+
+
+.. _rebuilding the system:
+
 Reinstalling on a running system
 ********************************
 
diff --git a/modules/outputs.nix b/modules/outputs.nix
index e0204eca..49d264cf 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -14,6 +14,7 @@ in
     ./outputs/squashfs.nix
     ./outputs/vmroot.nix
     ./outputs/extlinux.nix
+    ./outputs/updater
   ];
   options = {
     system.outputs = {
diff --git a/modules/outputs/updater/default.nix b/modules/outputs/updater/default.nix
new file mode 100644
index 00000000..e7bb2797
--- /dev/null
+++ b/modules/outputs/updater/default.nix
@@ -0,0 +1,36 @@
+{
+  config
+, pkgs
+, lib
+, ...
+}:
+let
+  inherit (lib) mkIf;
+  o = config.system.outputs;
+  inherit (pkgs) runCommand;
+  inherit (lib) mkOption types;
+  inherit (pkgs.buildPackages) min-copy-closure;
+in
+{
+  imports = [ ../system-configuration.nix ];
+  options.system.outputs.updater = mkOption {
+    type = types.package;
+    description = ''
+      updater
+      ******
+
+      For configurations with a writable filesystem, create a shell
+      script that runs on the build system and updates the device
+      over the network to the new configuration
+    '';
+  };
+
+  config.system.outputs.updater =
+    runCommand "buildUpdater" { } ''
+      mkdir -p $out/bin
+      substitute ${./update.sh} $out/bin/update.sh \
+         --subst-var-by toplevel ${o.systemConfiguration} \
+         --subst-var-by min_copy_closure ${min-copy-closure}
+      chmod +x  $out/bin/update.sh
+    '';
+}
diff --git a/pkgs/systemconfig/build-system-install.sh b/modules/outputs/updater/update.sh
similarity index 65%
rename from pkgs/systemconfig/build-system-install.sh
rename to modules/outputs/updater/update.sh
index 7bdac648..ccea5295 100755
--- a/pkgs/systemconfig/build-system-install.sh
+++ b/modules/outputs/updater/update.sh
@@ -1,22 +1,19 @@
 #!/usr/bin/env bash
 
-# this shell script can be run on the build system to
-# min-copy-closure the system configuration onto the device
-# and reboot/restart services as requested
+# this shell script is run on the build system to min-copy-closure the
+# system configuration onto the device and reboot/restart services as
+# requested
 
 die() {
     echo "$@"
     exit 1
 }
 
-# add min-copy-closure to the path. removing junk characters
-# inserted by default.nix (q.v.)
-min_copy_closure=@min-copy-closure@; PATH=${min_copy_closure//_/}/bin:$PATH
 
+PATH=@min_copy_closure@/bin:$PATH
 ssh_command=${SSH_COMMAND-ssh}
 
 reboot="reboot"
-
 case "$1" in
     "--no-reboot")
 	unset reboot
@@ -34,10 +31,11 @@ shift
 test -n "$target_host" || \
     die "Usage: $0 [--no-reboot] [--fast] target-host"
 
-toplevel=$(cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && readlink `pwd` )
+toplevel=$(realpath @toplevel@)
 test -e $toplevel/etc/nix-store-paths || die "missing etc/nix-store-paths, is this really a system configuration?"
 echo installing from systemConfiguration $toplevel to host $target_host
 
+$ssh_command $target_host uname -a || die "Can't ssh to $target_host"
 min-copy-closure $target_host $toplevel
 set -x
 $ssh_command $target_host $toplevel/bin/install
diff --git a/pkgs/systemconfig/default.nix b/pkgs/systemconfig/default.nix
index 4192667a..37ad3ea3 100644
--- a/pkgs/systemconfig/default.nix
+++ b/pkgs/systemconfig/default.nix
@@ -83,11 +83,6 @@ in attrset:
       $STRIP --remove-section=.note  --remove-section=.comment --strip-all activate -o $out/bin/activate
       ln -s ${s6-init-bin}/bin/init $out/bin/init
       cp -p ${writeFennel "restart-services" {} ./restart-services.fnl} $out/bin/restart-services
-      # obfuscate the store path of min-copy-closure so that the output
-      # closure doesn't include a bunch of build system stuff
-      f=${buildPackages.min-copy-closure}; f=$(echo $f | sed 's/\(.....\)/\1_/g')
-      substitute ${./build-system-install.sh} $out/install.sh --subst-var-by min-copy-closure $f
-      chmod +x $out/install.sh
       cat > $out/bin/install <<EOF
       #!/bin/sh -e
       prefix=\''${1-/}

From 4ea1cf7f321a8c4ef1001a42f36e0fdfd8c36fe9 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Fri, 20 Dec 2024 22:26:40 +0000
Subject: [PATCH 18/29] rt3200 better install docs

---
 devices/belkin-rt3200/default.nix | 35 ++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/devices/belkin-rt3200/default.nix b/devices/belkin-rt3200/default.nix
index 4a6fd0ec..4436e713 100644
--- a/devices/belkin-rt3200/default.nix
+++ b/devices/belkin-rt3200/default.nix
@@ -7,12 +7,10 @@
     and is "work in progress" in Liminix.
 
     .. note:: The factory flash image contains ECC errors that make it
-              incompatible with Liminix: you need to use the `OpenWrt
+              incompatible with Liminix: use the `OpenWrt
               UBI Installer <https://github.com/dangowrt/owrt-ubi-installer>`_ to
-              rewrite the partition layout before you can flash
-              Liminix onto it (or even use it with
-              :ref:`system-outputs-tftpboot`, if you want the wireless
-              to work).
+              rewrite the partition layout before you can use
+              Liminix with it
 
     Hardware summary
     ================
@@ -27,8 +25,31 @@
     Installation
     ============
 
-    Installation is currently a manual process (you need a :ref:`serial <serial>` conection and
-    TFTP) following the instructions at :ref:`system-outputs-ubimage`
+    Installation is currently a manual process.
+
+    Preparation
+    -----------
+
+    To prepare the device for Liminix you first need to use the
+    `OpenWrt UBI Installer
+    <https://github.com/dangowrt/owrt-ubi-installer>`_ image to
+    rewrite the flash layout. You can do this in onw of two ways:
+    either follow the instructions to do it through the vendor web
+    interface, or you can drop to U-boot and use TFTP
+
+    .. code-block:: console
+
+        MT7622> setenv ipaddr 10.0.0.6
+        MT7622> setenv serverip 10.0.0.1
+        MT7622> tftpboot 0x42000000  openwrt-mediatek-mt7622-linksys_e8450-ubi-initramfs-recovery-installer.itb
+        MT7622> bootm 0x42000000
+
+     Once it's finished booted into Linux you can safely reboot
+
+     Installing Liminix
+     ------------------
+
+     This is a manual process: you need a :ref:`serial <serial>` conection and TFTP : follow the instructions at :ref:`system-outputs-ubimage`
 
 '';
 

From 6bfbdf352d3654503bc4421ecedf01c28efd82b9 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sun, 22 Dec 2024 16:01:38 +0000
Subject: [PATCH 19/29] bordervm: expose ssh on port 2222

---
 bordervm-configuration.nix | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/bordervm-configuration.nix b/bordervm-configuration.nix
index ffd18f02..c8347d16 100644
--- a/bordervm-configuration.nix
+++ b/bordervm-configuration.nix
@@ -102,12 +102,18 @@ in {
     systemd.services.sshd.wantedBy = pkgs.lib.mkForce [ "multi-user.target" ];
 
     virtualisation = {
-      forwardPorts = [ {
-        from = "host";
-        host.port = 7654;
-#        guest.address = "10.0.2.15";
-        guest.port =7654;
-      } ];
+      forwardPorts = [
+        {
+          from = "host";
+          host.port = 7654;
+          #        guest.address = "10.0.2.15";
+          guest.port =7654;
+        }
+        {
+          host.port = 2222;
+          guest.address = "10.0.2.15";
+          guest.port = 22;
+        }];
       qemu = {
         networkingOptions = [ ];
         options =

From ebb4d4a8316c055120e58432703ecdbdf30890ee Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sun, 22 Dec 2024 16:03:24 +0000
Subject: [PATCH 20/29] think

---
 THOUGHTS.txt | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 1 deletion(-)

diff --git a/THOUGHTS.txt b/THOUGHTS.txt
index 6c7a467f..d46f4bbe 100644
--- a/THOUGHTS.txt
+++ b/THOUGHTS.txt
@@ -6565,6 +6565,72 @@ use status and in fact there isn't one for reserved-memory
 we could use global config to enable pstore_msg and check it in
 the device module to enable the needed hw support
 
+Tue Dec 17 23:39:28 GMT 2024
 
+I think we can just stick a tee in the fallback logger pipeline that
+writes to /dev/pmsg0
 
-00PA727 00PA735
+Need to check it's a circular buffer
+
+do we want to do anything about recovering the log on boot?
+- we could just copy it to /run/log
+- if we have backfilling for shipped logs (we don't yet)
+  then we might want to ship it - but that may result in duplicate
+  logs if some of it was shipped before the crash
+
+perhaps we should truncate pmsg0 on orderly shutdown? or maybe it's
+good to see the late shutdown logs.
+
+Thu Dec 19 13:40:39 GMT 2024
+
+although we have PSTORE_foo in the omnia kconfig, I think this might
+be just because I copied it from RT3200
+
+Thu Dec 19 14:15:43 GMT 2024
+
+Omnia is not in ci.nix, and it's not trivial to add it because there
+is no output in the ci.nix configuration that makes sense for omnia.
+
+... OK, fixed by adding system-configuration as an independent module
+and importing in device config
+
+Thu Dec 19 21:59:47 GMT 2024
+
+The build-system shell script in outputs.systemConfiguration
+is ugly and requires we do bad things to avoid sucking build
+system stuff into the config
+
+I propose we make it a separate derivation.
+
+But first maybe we could improve some names
+
+Sun Dec 22 14:23:02 GMT 2024
+
+MT7622> echo $boot_default
+if env exists flag_recover ; then else run bootcmd ; fi ; run boot_recovery ; setenv replacevol 1 ; run boot_tftp_for
+ever
+MT7622> echo $bootcmd
+if pstore check ; then run boot_recovery ; else run boot_ubi ; fi
+MT7622> echo $boot_ubi
+ubi part ubi && run boot_production ; run boot_recovery
+MT7622> echo $boot_production
+led $bootled_pwr on ; run ubi_read_production && bootm $loadaddr#$bootconf ; led $bootled_pwr off
+MT7622> echo $ubi_read_production
+ubi read $loadaddr fit && iminfo $loadaddr && run ubi_prepare_rootfs
+MT7622> echo $ubi_prepare_rootfs
+if ubi check rootfs_data ; then else if env exists rootfs_data_max ; then ubi create rootfs_data $rootfs_data_max dynamic || ubi create rootfs_data - dynamic ; else ubi create rootfs_data - dynamic ; fi ; fi
+MT7622> echo $bootconf
+config-1
+MT7622> run boot_ubi
+UBI partition 'ubi' already selected
+No size specified -> Using max size (126976)
+Read 126976 bytes from volume fit to 0000000048000000
+
+## Checking Image at 48000000 ...
+Unknown image format!
+No size specified -> Using max size (7491584)
+Read 7491584 bytes from volume recovery to 0000000048000000
+## Loading kernel from FIT Image at 48000000 ...
+   Using 'config-1' configuration
+   Trying 'kernel-1' kernel subimage
+     Description:  ARM64 OpenWrt Linux-6.6.45

From ac189f29772da8f3d38288ddea13dc77af5a10a1 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sun, 22 Dec 2024 17:27:59 +0000
Subject: [PATCH 21/29] outputs.zimage -> outputs.kernel.zImage

remove config option/derivation in favour of accessing
as output of the kernel derivation (matches what we do
with e.g. modulesupport)
---
 modules/kernel/default.nix   | 14 +++++---------
 modules/outputs.nix          | 12 +-----------
 modules/outputs/extlinux.nix |  2 +-
 modules/outputs/tftpboot.nix |  2 +-
 4 files changed, 8 insertions(+), 22 deletions(-)

diff --git a/modules/kernel/default.nix b/modules/kernel/default.nix
index 9ebb8649..e5431fec 100644
--- a/modules/kernel/default.nix
+++ b/modules/kernel/default.nix
@@ -68,19 +68,15 @@ in {
     };
   };
   config = {
-    system.outputs =
+    system.outputs.kernel =
       let
         mergedConfig = mergeConditionals
           config.kernel.config
           config.kernel.conditionalConfig;
-        k = liminix.builders.kernel.override {
-          config = mergedConfig;
-          inherit (config.kernel) version src extraPatchPhase;
-          targets = config.kernel.makeTargets;
-        };
-      in {
-        kernel = k.vmlinux;
-        zimage = k.zImage;
+      in liminix.builders.kernel.override {
+        config = mergedConfig;
+        inherit (config.kernel) version src extraPatchPhase;
+        targets = config.kernel.makeTargets;
       };
 
     kernel = rec {
diff --git a/modules/outputs.nix b/modules/outputs.nix
index 49d264cf..a0cda7dc 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -28,17 +28,7 @@ in
           kernel
           ******
 
-          Kernel vmlinux file (usually ELF)
-        '';
-      };
-      zimage = mkOption {
-        type = types.package;
-        internal = true;
-        description = ''
-          zimage
-          ******
-
-          Kernel in compressed self-extracting package
+          Kernel package (multi-output derivation)
         '';
       };
       dtb = mkOption {
diff --git a/modules/outputs/extlinux.nix b/modules/outputs/extlinux.nix
index 6f733452..6eb74131 100644
--- a/modules/outputs/extlinux.nix
+++ b/modules/outputs/extlinux.nix
@@ -24,7 +24,7 @@ in {
       cd $out
       ${if wantsDtb then "cp ${o.dtb} dtb" else "true"}
       cp ${o.initramfs} initramfs
-      cp ${o.zimage} kernel
+      cp ${o.kernel.zImage} kernel
       mkdir extlinux
       cat > extlinux/extlinux.conf << _EOF
       menu title Liminix
diff --git a/modules/outputs/tftpboot.nix b/modules/outputs/tftpboot.nix
index 63fc4ead..e4d6a031 100644
--- a/modules/outputs/tftpboot.nix
+++ b/modules/outputs/tftpboot.nix
@@ -61,7 +61,7 @@ in {
           o = config.system.outputs;
           image = let choices = {
             uimage = o.uimage;
-            zimage = o.zimage;
+            zimage = o.kernel.zImage;
           }; in choices.${cfg.kernelFormat};
           bootCommand = let choices = {
             uimage = "bootm";

From f07a38b0fd822d401ac6b170ce9b7c57c78f009d Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sun, 22 Dec 2024 21:10:07 +0000
Subject: [PATCH 22/29] extract uimage output module into own file

---
 modules/outputs.nix        | 18 +-----------------
 modules/outputs/uimage.nix | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 17 deletions(-)
 create mode 100644 modules/outputs/uimage.nix

diff --git a/modules/outputs.nix b/modules/outputs.nix
index a0cda7dc..afd973b9 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -14,6 +14,7 @@ in
     ./outputs/squashfs.nix
     ./outputs/vmroot.nix
     ./outputs/extlinux.nix
+    ./outputs/uimage.nix
     ./outputs/updater
   ];
   options = {
@@ -41,16 +42,6 @@ in
           Compiled device tree (FDT) for the target device
         '';
       };
-      uimage = mkOption {
-        type = types.package;
-        internal = true;
-        description = ''
-          uimage
-          ******
-
-          Combined kernel and FDT in uImage (U-Boot compatible) format
-        '';
-      };
       tplink-safeloader = mkOption {
         type = types.package;
       };
@@ -100,13 +91,6 @@ in
           "${o.kernel.headers}/include"
         ];
       };
-      uimage = liminix.builders.uimage {
-        commandLine = concatStringsSep " " config.boot.commandLine;
-        inherit (config.boot) commandLineDtbNode;
-        inherit (config.hardware) loadAddress entryPoint alignment;
-        inherit (config.boot) imageFormat;
-        inherit (o) kernel dtb;
-      };
       rootdir =
         let
           inherit (pkgs.pkgsBuildBuild) runCommand;
diff --git a/modules/outputs/uimage.nix b/modules/outputs/uimage.nix
new file mode 100644
index 00000000..b36ef60a
--- /dev/null
+++ b/modules/outputs/uimage.nix
@@ -0,0 +1,30 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+let
+  inherit (lib) mkOption types concatStringsSep;
+  inherit (pkgs) liminix writeText;
+  o = config.system.outputs;
+in
+{
+  options.system.outputs.uimage = mkOption {
+    type = types.package;
+    internal = true;
+    description = ''
+      uimage
+      ******
+
+      Combined kernel and FDT in uImage (U-Boot compatible) format
+    '';
+  };
+  config.system.outputs.uimage = liminix.builders.uimage {
+    commandLine = concatStringsSep " " config.boot.commandLine;
+    inherit (config.boot) commandLineDtbNode;
+    inherit (config.hardware) loadAddress entryPoint alignment;
+    inherit (config.boot) imageFormat;
+    inherit (o) kernel dtb;
+  };
+}

From ed02d02767f34cbe335f53324ee447a746e57bb4 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sun, 22 Dec 2024 21:12:36 +0000
Subject: [PATCH 23/29] bump NEWS

---
 NEWS | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index b8ad2ffe..d4ee5892 100644
--- a/NEWS
+++ b/NEWS
@@ -151,4 +151,9 @@ with a writable filesystem is to build the updater output
     nix-build  -I liminix-config=hosts/myhost.nix --argstr deviceName turris-omnia -A outputs.updater
 
 and then run the generated `update.sh` script. See 
-https://www.liminix.org/doc/admin.html#updating-an-installed-system
\ No newline at end of file
+https://www.liminix.org/doc/admin.html#updating-an-installed-system
+
+2024-12-22
+
+outputs.zimage is now outputs.kernel.zImage. This is unlikely to
+affect many people at all but I mention it anyway.
\ No newline at end of file

From 5c78338d71240e20fe1532964198a25214e42f4e Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sun, 22 Dec 2024 23:24:11 +0000
Subject: [PATCH 24/29] make mtdutils use no-systemd util-linux

---
 overlay.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/overlay.nix b/overlay.nix
index 0f84ca58..bf302cfd 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -218,11 +218,11 @@ extraPkgs // {
     ] ++ final.lib.optionals (o ? patches) o.patches;
   });
 
-  mtdutils = prev.mtdutils.overrideAttrs(o: {
+  mtdutils = (prev.mtdutils.overrideAttrs(o: {
     patches = (if o ? patches then o.patches else []) ++ [
       ./pkgs/mtdutils/0001-mkfs.jffs2-add-graft-option.patch
     ];
-  });
+  })).override { util-linux = final.util-linux-small ; };
 
   nftables = prev.nftables.overrideAttrs(o: {
     configureFlags = [

From a7b5f8067486f3a51372c6431f64a3bc6f2cc653 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Mon, 23 Dec 2024 00:09:31 +0000
Subject: [PATCH 25/29] rename extlinux output to bootfiles

this is in preparation for introducing other non-extlinux
modules that populate /boot
---
 modules/outputs.nix          | 10 ++++++++--
 modules/outputs/extlinux.nix |  8 ++------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/modules/outputs.nix b/modules/outputs.nix
index afd973b9..4797d4da 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -64,6 +64,12 @@ in
           directory of files to package into root filesystem
         '';
       };
+      bootfiles = mkOption {
+        type = types.nullOr types.package;
+        internal = true;
+        default = null;
+        # description = "";
+      };
       bootablerootdir = mkOption {
         type = types.package;
         internal = true;
@@ -107,8 +113,8 @@ in
         let inherit (pkgs.pkgsBuildBuild) runCommand;
         in runCommand "add-slash-boot" { } ''
           cp -a ${o.rootdir} $out
-          ${if config.boot.loader.extlinux.enable
-            then "(cd $out && chmod -R +w . && rmdir boot && cp -a ${o.extlinux} boot)"
+          ${if o.bootfiles != null
+            then "(cd $out && chmod -R +w . && rmdir boot && cp -a ${o.bootfiles} boot)"
             else ""
            }
          '';
diff --git a/modules/outputs/extlinux.nix b/modules/outputs/extlinux.nix
index 6eb74131..70b71fdd 100644
--- a/modules/outputs/extlinux.nix
+++ b/modules/outputs/extlinux.nix
@@ -12,14 +12,10 @@ let
   cmdline = concatStringsSep " " config.boot.commandLine;
   wantsDtb = config.hardware.dts ? src && config.hardware.dts.src != null;
 in {
-  options.system.outputs.extlinux = mkOption {
-    type = types.package;
-    # description = "";
-  };
   options.boot.loader.extlinux.enable = mkEnableOption "extlinux";
 
   config = mkIf cfg.enable {
-    system.outputs.extlinux = pkgs.runCommand "extlinux" {} ''
+    system.outputs.bootfiles = pkgs.runCommand "extlinux" {} ''
       mkdir $out
       cd $out
       ${if wantsDtb then "cp ${o.dtb} dtb" else "true"}
@@ -37,7 +33,7 @@ in {
       _EOF
     '';
     filesystem = dir {
-      boot = symlink config.system.outputs.extlinux;
+      boot = symlink config.system.outputs.bootfiles;
     };
   };
 }

From 1347937345de22a08010b4a01c1c430045bfa723 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Mon, 23 Dec 2024 10:31:22 +0000
Subject: [PATCH 26/29] rename file

---
 examples/recovery.nix                               | 1 -
 modules/outputs.nix                                 | 2 +-
 modules/outputs/{extlinux.nix => boot-extlinux.nix} | 0
 3 files changed, 1 insertion(+), 2 deletions(-)
 rename modules/outputs/{extlinux.nix => boot-extlinux.nix} (100%)

diff --git a/examples/recovery.nix b/examples/recovery.nix
index 9b0320e6..7391a700 100644
--- a/examples/recovery.nix
+++ b/examples/recovery.nix
@@ -22,7 +22,6 @@ in rec {
     ../modules/outputs/ubimage.nix
     ../modules/outputs/jffs2.nix
     ../modules/outputs/ext4fs.nix
-    ../modules/outputs/extlinux.nix
   ];
 
   kernel.config = {
diff --git a/modules/outputs.nix b/modules/outputs.nix
index 4797d4da..da5cdac8 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -13,7 +13,7 @@ in
   imports = [
     ./outputs/squashfs.nix
     ./outputs/vmroot.nix
-    ./outputs/extlinux.nix
+    ./outputs/boot-extlinux.nix
     ./outputs/uimage.nix
     ./outputs/updater
   ];
diff --git a/modules/outputs/extlinux.nix b/modules/outputs/boot-extlinux.nix
similarity index 100%
rename from modules/outputs/extlinux.nix
rename to modules/outputs/boot-extlinux.nix

From db4f098c02f3597d6fe696fc9741a9c3824e0505 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Mon, 23 Dec 2024 11:21:58 +0000
Subject: [PATCH 27/29] add fit bootloader

this is for the belkin rt3200, whose uboot doesn't do
extlinux but can load a fit from a ubifs. It adds the
a kernel+dtb as /boot/fit
---
 modules/outputs.nix          |  1 +
 modules/outputs/boot-fit.nix | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 modules/outputs/boot-fit.nix

diff --git a/modules/outputs.nix b/modules/outputs.nix
index da5cdac8..6da7daaa 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -14,6 +14,7 @@ in
     ./outputs/squashfs.nix
     ./outputs/vmroot.nix
     ./outputs/boot-extlinux.nix
+    ./outputs/boot-fit.nix
     ./outputs/uimage.nix
     ./outputs/updater
   ];
diff --git a/modules/outputs/boot-fit.nix b/modules/outputs/boot-fit.nix
new file mode 100644
index 00000000..cf998ba3
--- /dev/null
+++ b/modules/outputs/boot-fit.nix
@@ -0,0 +1,27 @@
+{
+  config
+, pkgs
+, lib
+, ...
+}:
+let
+  inherit (lib) mkIf mkEnableOption mkOption types concatStringsSep;
+  inherit (pkgs.pseudofile) dir symlink;
+  cfg = config.boot.loader.fit;
+  o = config.system.outputs;
+  cmdline = concatStringsSep " " config.boot.commandLine;
+  wantsDtb = config.hardware.dts ? src && config.hardware.dts.src != null;
+in {
+  options.boot.loader.fit.enable = mkEnableOption "FIT in /boot";
+
+  config = mkIf cfg.enable {
+    system.outputs.bootfiles = pkgs.runCommand "boot-fit" {} ''
+      mkdir $out
+      cd $out
+      cp ${o.uimage} fit
+    '';
+    filesystem = dir {
+      boot = symlink config.system.outputs.bootfiles;
+    };
+  };
+}

From f3fadd5cd765e1b6179a3e7dd389ad8a5cea3a14 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Tue, 24 Dec 2024 12:20:48 +0000
Subject: [PATCH 28/29] think

---
 THOUGHTS.txt | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/THOUGHTS.txt b/THOUGHTS.txt
index d46f4bbe..dbf996ef 100644
--- a/THOUGHTS.txt
+++ b/THOUGHTS.txt
@@ -6634,3 +6634,39 @@ Read 7491584 bytes from volume recovery to 0000000048000000
    Using 'config-1' configuration
    Trying 'kernel-1' kernel subimage
      Description:  ARM64 OpenWrt Linux-6.6.45
+
+Sun Dec 22 17:39:56 GMT 2024
+
+From the output above it looks like the device I have plugged in has
+an openwrt "recovery" image but not a "production" image
+
+It also looks like it will be quite hard work to persuade it to boot
+from usb or anything. It doesn't have any of the extlinux stuff
+but it does have uefi for what that's worth
+
+default boot_production command reads a ubi volume called 'fit' and
+calls bootm on what it finds
+
+we could define boot_production to ubifsmount liminix; ubifs load
+<addr> <filename> (which is a fit) and bootm it. *presumably* we could
+do this from the openwrt recovery image
+
+but could we install the whole system using said recovery image?  I
+expect we could do, it only requires getting a tarball onto it and
+unpacking it
+
+however, extlinux is not going to be helpful
+(actually it might be a bit, if we ask it to write the fit as
+well as/instead of the individual files)
+
+maybe we need separate concepts of "the filesystem contains
+stuff we need for boot" and "the stuff we need is the stuff
+that extlinux needs"
+
+each bootloader makes an output called bootfiles, and
+the bootablerootdir output copies from bootfiles
+
+Mon Dec 23 18:28:50 GMT 2024
+
+it might be worth moving ubi option decls into the hardware module, if
+they're hardware-dependent

From a89f866bf0a054dda12efaec52c34b51ab1ee24a Mon Sep 17 00:00:00 2001
From: Arnout Engelen <arnout@bzzt.net>
Date: Tue, 17 Dec 2024 20:24:14 +0100
Subject: [PATCH 29/29] use Linux kernel sources associated with openwrt by
 default

---
 devices/belkin-rt3200/default.nix  |  5 -----
 devices/families/qemu.nix          |  5 -----
 devices/gl-ar750/default.nix       |  6 ------
 devices/gl-mt300a/default.nix      |  5 -----
 devices/gl-mt300n-v2/default.nix   |  5 -----
 devices/tp-archer-ax23/default.nix |  5 -----
 devices/zyxel-nwa50ax/default.nix  |  6 ------
 modules/kernel/default.nix         |  6 +++---
 pkgs/openwrt/default.nix           | 11 +++++++++++
 9 files changed, 14 insertions(+), 40 deletions(-)

diff --git a/devices/belkin-rt3200/default.nix b/devices/belkin-rt3200/default.nix
index 4436e713..396a739d 100644
--- a/devices/belkin-rt3200/default.nix
+++ b/devices/belkin-rt3200/default.nix
@@ -76,11 +76,6 @@
       ];
       config = {
     kernel = {
-      src = pkgs.pkgsBuildBuild.fetchurl {
-        name = "linux.tar.gz";
-        url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
-        hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
-      };
       extraPatchPhase = ''
           ${pkgs.openwrt.applyPatches.mediatek}
       '';
diff --git a/devices/families/qemu.nix b/devices/families/qemu.nix
index ce28d884..ccf054c1 100644
--- a/devices/families/qemu.nix
+++ b/devices/families/qemu.nix
@@ -5,11 +5,6 @@
   ];
   config = {
     kernel = {
-      src = pkgs.pkgsBuildBuild.fetchurl {
-        name = "linux.tar.gz";
-        url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
-        hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
-      };
       config = {
         MTD = "y";
         MTD_BLOCK = "y";
diff --git a/devices/gl-ar750/default.nix b/devices/gl-ar750/default.nix
index 7be4c904..a7f18a6c 100644
--- a/devices/gl-ar750/default.nix
+++ b/devices/gl-ar750/default.nix
@@ -161,12 +161,6 @@
         appendDTB = true;
       };
       kernel = {
-        src = pkgs.pkgsBuildBuild.fetchurl {
-          name = "linux.tar.gz";
-          url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
-          hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
-        };
-
         # Mainline linux 5.19 doesn't have device-tree support for
         # this device or even for the SoC, so we use the extensive
         # OpenWrt kernel patches
diff --git a/devices/gl-mt300a/default.nix b/devices/gl-mt300a/default.nix
index 6659951f..d972e44c 100644
--- a/devices/gl-mt300a/default.nix
+++ b/devices/gl-mt300a/default.nix
@@ -114,11 +114,6 @@
      };
 
       kernel = {
-        src = pkgs.fetchurl {
-          name = "linux.tar.gz";
-          url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
-          hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
-        };
         extraPatchPhase = ''
           ${openwrt.applyPatches.ramips}
           ${openwrt.applyPatches.rt2x00}
diff --git a/devices/gl-mt300n-v2/default.nix b/devices/gl-mt300n-v2/default.nix
index ae12317d..901bfaa4 100644
--- a/devices/gl-mt300n-v2/default.nix
+++ b/devices/gl-mt300n-v2/default.nix
@@ -125,11 +125,6 @@
       };
 
       kernel = {
-        src = pkgs.fetchurl {
-          name = "linux.tar.gz";
-          url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
-          hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
-        };
         extraPatchPhase = ''
           ${openwrt.applyPatches.ramips}
         '';
diff --git a/devices/tp-archer-ax23/default.nix b/devices/tp-archer-ax23/default.nix
index 64eff0fd..6c6519c3 100644
--- a/devices/tp-archer-ax23/default.nix
+++ b/devices/tp-archer-ax23/default.nix
@@ -50,11 +50,6 @@
       ];
       config = {
         kernel = {
-          src = pkgs.pkgsBuildBuild.fetchurl {
-            name = "linux.tar.gz";
-            url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
-            hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
-          };
           extraPatchPhase = ''
             ${pkgs.openwrt.applyPatches.ramips}
           '';
diff --git a/devices/zyxel-nwa50ax/default.nix b/devices/zyxel-nwa50ax/default.nix
index 9c9b9d9c..710473d2 100644
--- a/devices/zyxel-nwa50ax/default.nix
+++ b/devices/zyxel-nwa50ax/default.nix
@@ -250,14 +250,8 @@
       #  IMAGE/ramboot-factory.bin := append-kernel | pad-to $$(KERNEL_SIZE) | append-ubi
 
       kernel = {
-        src = pkgs.fetchurl {
-          name = "linux.tar.gz";
-          url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
-          hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
-        };
         extraPatchPhase = ''
           ${openwrt.applyPatches.ramips}
-
         '';
         config = {
 
diff --git a/modules/kernel/default.nix b/modules/kernel/default.nix
index e5431fec..373bfcc2 100644
--- a/modules/kernel/default.nix
+++ b/modules/kernel/default.nix
@@ -6,7 +6,7 @@
 { lib, pkgs, config, ...}:
 let
   inherit (lib) mkOption types ;
-  inherit (pkgs) liminix;
+  inherit (pkgs) liminix openwrt;
 
   mergeConditionals = conf : conditions :
     # for each key in conditions, if it is present in conf
@@ -21,8 +21,8 @@ let
 in {
   options = {
     kernel = {
-      src = mkOption { type = types.path; } ;
-      version = mkOption { type = types.str; default = "5.15.137";} ;
+      src = mkOption { type = types.path; default = openwrt.kernelSrc; } ;
+      version = mkOption { type = types.str; default = openwrt.kernelVersion;} ;
       modular = mkOption {
         type = types.bool;
         default = true;
diff --git a/pkgs/openwrt/default.nix b/pkgs/openwrt/default.nix
index 2fb16ec1..7376dd8b 100644
--- a/pkgs/openwrt/default.nix
+++ b/pkgs/openwrt/default.nix
@@ -29,6 +29,17 @@ let
   '';
 in {
   inherit src;
+
+  # The kernel sources typically used with this version of openwrt
+  # You can find this in `include/kernel-5.15` or similar in the
+  # openwrt sources
+  kernelSrc = pkgsBuildBuild.fetchurl {
+    name = "linux.tar.gz";
+    url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
+    hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
+  };
+  kernelVersion = "5.15.137";
+
   applyPatches.ath79 = doPatch "ath79";
   applyPatches.ramips = doPatch "ramips";
   applyPatches.mediatek = doPatch "mediatek"; # aarch64