erase full flash, it seems to help with jffs2

the (openwrt?) magic that autodetects it based on mtd labels
won't work with a two-stage boot

devices/gl-ar750/default.nix

@@ -89,7 +89,7 @@
           size ="0xfa0000";
           eraseBlockSize = "65536";
         };
-        rootDevice = "1f05";
+        rootDevice = "/dev/mtdblock5";
         dts = {
           src = "${openwrt.src}/target/linux/ath79/dts/qca9531_glinet_gl-ar750.dts";
           includes =  [

devices/gl-mt300a/default.nix

@@ -47,7 +47,7 @@
           size ="0xf80000";
           eraseBlockSize = "65536";
         };
-        rootDevice = "1f05";
+        rootDevice = "/dev/mtdblock5";
 
         dts = {
           src = "${openwrt.src}/target/linux/ramips/dts/mt7620a_glinet_gl-mt300a.dts";

devices/gl-mt300n-v2/default.nix

@@ -44,7 +44,7 @@
           size = "0xfb0000";
           eraseBlockSize = "65536";
         };
-        rootDevice = "1f05";
+        rootDevice = "/dev/mtdblock5";
 
         dts = {
           src = "${openwrt.src}/target/linux/ramips/dts/mt7628an_glinet_gl-mt300n-v2.dts";

examples/rotuer.nix

@@ -25,7 +25,7 @@ let
 in rec {
   boot = {
     tftp = {
-      enable = true;
+      freeSpaceBytes = 3 * 1024 * 1024;
       serverip = "10.0.0.1";
       ipaddr = "10.0.0.8";
     };

modules/base.nix

@@ -2,7 +2,6 @@
 let
   inherit (lib) mkEnableOption mkOption types isDerivation hasAttr ;
   inherit (pkgs.pseudofile) dir symlink;
-#  inherit (pkgs) busybox;
   inherit (pkgs.liminix.networking) address interface;
   inherit (pkgs.liminix.services) bundle;
 
@@ -52,7 +51,6 @@ in {
         # the right to change them if I think of better ones.
         ipaddr =  mkOption { type = types.str; };
         serverip =  mkOption { type = types.str; };
-        enable =  mkOption { type = types.boolean; };
       };
     };
   };
@@ -119,6 +117,7 @@ in {
     };
     boot.commandLine = [
       "console=ttyS0,115200 panic=10 oops=panic init=/bin/init loglevel=8"
+      "root=${config.hardware.rootDevice}"
       "rootfstype=${config.rootfsType}"
       "fw_devlink=off"
     ];

modules/flashimage.nix

@@ -53,7 +53,7 @@ in {
           setenv serverip ${tftp.serverip}
           setenv ipaddr ${tftp.ipaddr}
           tftp 0x$(printf %x ${tftp.loadAddress}) result/firmware.bin
-          erase 0x$(printf %x ${flash.address}) +\''${filesize})
+          erase 0x$(printf %x ${flash.address}) +${flash.size}
           cp.b 0x$(printf %x ${tftp.loadAddress}) 0x$(printf %x ${flash.address}) \''${filesize}
           echo command line was ${builtins.toJSON (concatStringsSep " " config.boot.commandLine)}
           EOF

modules/initramfs.nix

@@ -31,6 +31,11 @@ in
           dir /dev 0755 0 0
           nod /dev/console 0600 0 0 c 5 1
           nod /dev/mtdblock0 0600 0 0 b 31 0
+          nod /dev/mtdblock1 0600 0 0 b 31 1
+          nod /dev/mtdblock2 0600 0 0 b 31 2
+          nod /dev/mtdblock3 0600 0 0 b 31 3
+          nod /dev/mtdblock4 0600 0 0 b 31 4
+          nod /dev/mtdblock5 0600 0 0 b 31 5
           dir /target 0755 0 0
           dir /target/persist 0755 0 0
           dir /target/nix 0755 0 0

modules/tftpboot.nix

@@ -9,6 +9,10 @@ let
   cfg = config.boot.tftp;
 in {
   imports = [ ./ramdisk.nix ];
+  options.boot.tftp.freeSpaceBytes = mkOption {
+    type = types.int;
+    default = 0;
+  };
   config = {
     boot.ramdisk.enable = true;
 
@@ -33,8 +37,8 @@ in {
           uimageSize=$(($(stat -L -c %s ${config.outputs.uimage}) + 0x1000 &(~0xfff)))
           rootfsStart=0x$(printf %x $((${cfg.loadAddress} + 0x100000 + $uimageSize)))
           rootfsBytes=$(($(stat -L -c %s ${config.outputs.rootfs}) + 0x100000 &(~0xfffff)))
-          rootfsMb=$(($rootfsBytes >> 20))
-          cmd="mtdparts=phram0:''${rootfsMb}M(rootfs) phram.phram=phram0,''${rootfsStart},''${rootfsMb}Mi,${config.hardware.flash.eraseBlockSize} memmap=''${rootfsMb}M\$''${rootfsStart} root=/dev/mtdblock0";
+          rootfsBytes=$(($rootfsBytes + ${toString cfg.freeSpaceBytes} ))
+          cmd="mtdparts=phram0:''${rootfsMb}M(rootfs) phram.phram=phram0,''${rootfsStart},''${rootfsBytes},${config.hardware.flash.eraseBlockSize} memmap=''${rootfsBytes}\$''${rootfsStart} root=/dev/mtdblock0";
 
           cat > $out << EOF
           setenv serverip ${cfg.serverip}