{
  description = ''
    TP-Link Archer AX23 / AX1800 Dual Band Wi-Fi 6 Router
    *****************************************************

    Hardware summary
    ================

    - MediaTek MT7621 (880MHz)
    - 16MB Flash
    - 128MB RAM
    - WLan hardware: Mediatek MT7905, MT7975
  '';

  system = {
    crossSystem = {
      config = "mipsel-unknown-linux-musl";
      gcc = {
        abi = "32";
        # https://openwrt.org/docs/techref/instructionset/mipsel_24kc
        arch = "24kc";
      };
    };
  };

  module = {pkgs, config, lib, lim, ... }:
    let firmware = pkgs.stdenv.mkDerivation {
          name = "wlan-firmware";
          phases = ["installPhase"];
          installPhase = ''
            mkdir $out
            cp ${pkgs.linux-firmware}/lib/firmware/mediatek/{mt7915,mt7615,mt7622}* $out
          '';
        };
    in {
      imports = [
        ../../modules/arch/mipsel.nix
        ../../modules/outputs/tftpboot.nix
        ../../modules/outputs/ubifs.nix
      ];
      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}
          '';
          config = {
ARCH_32BIT_OFF_T="y";
ARCH_HIBERNATION_POSSIBLE="y";
ARCH_KEEP_MEMBLOCK="y";
ARCH_MMAP_RND_BITS_MAX="15";
ARCH_MMAP_RND_COMPAT_BITS_MAX="15";
ARCH_SUSPEND_POSSIBLE="y";
AT803X_PHY="y";
BLK_MQ_PCI="y";
BOARD_SCACHE="y";
CEVT_R4K="y";
CLKSRC_MIPS_GIC="y";
CLK_MT7621="y";
CLOCKSOURCE_WATCHDOG="y";
CLONE_BACKWARDS="y";
CMDLINE_BOOL="y";
COMMON_CLK="y";
COMPAT_32BIT_TIME="y";
CPU_GENERIC_DUMP_TLB="y";
CPU_HAS_DIEI="y";
CPU_HAS_PREFETCH="y";
CPU_HAS_RIXI="y";
CPU_HAS_SYNC="y";
CPU_LITTLE_ENDIAN="y";
CPU_MIPS32="y";
CPU_MIPS32_R2="y";
CPU_MIPSR2="y";
CPU_MIPSR2_IRQ_EI="y";
CPU_MIPSR2_IRQ_VI="y";
CPU_NEEDS_NO_SMARTMIPS_OR_MICROMIPS="y";
CPU_R4K_CACHE_TLB="y";
CPU_RMAP="y";
CPU_SUPPORTS_32BIT_KERNEL="y";
CPU_SUPPORTS_HIGHMEM="y";
CPU_SUPPORTS_MSA="y";
CRC16="y";
CRYPTO_DEFLATE="y";
CRYPTO_HASH_INFO="y";
CRYPTO_LIB_BLAKE2S_GENERIC="y";
CRYPTO_LIB_POLY1305_RSIZE="2";
CRYPTO_LZO="y";
CRYPTO_ZSTD="y";
CSRC_R4K="y";
DIMLIB="y";
DMA_NONCOHERENT="y";
DTB_RT_NONE="y";
DTC="y";
EARLY_PRINTK="y";
FIXED_PHY="y";
FWNODE_MDIO="y";
FW_LOADER_PAGED_BUF="y";
GENERIC_ATOMIC64="y";
GENERIC_CLOCKEVENTS="y";
GENERIC_CMOS_UPDATE="y";
GENERIC_CPU_AUTOPROBE="y";
GENERIC_FIND_FIRST_BIT="y";
GENERIC_GETTIMEOFDAY="y";
GENERIC_IOMAP="y";
GENERIC_IRQ_CHIP="y";
GENERIC_IRQ_EFFECTIVE_AFF_MASK="y";
GENERIC_IRQ_SHOW="y";
GENERIC_LIB_ASHLDI3="y";
GENERIC_LIB_ASHRDI3="y";
GENERIC_LIB_CMPDI2="y";
GENERIC_LIB_LSHRDI3="y";
GENERIC_LIB_UCMPDI2="y";
GENERIC_PCI_IOMAP="y";
GENERIC_PHY="y";
GENERIC_PINCONF="y";
GENERIC_SCHED_CLOCK="y";
GENERIC_SMP_IDLE_THREAD="y";
GENERIC_TIME_VSYSCALL="y";
GLOB="y";
GPIOLIB_IRQCHIP="y";
GPIO_CDEV="y";
GPIO_GENERIC="y";
GPIO_MT7621="y";
GRO_CELLS="y";
HANDLE_DOMAIN_IRQ="y";
HARDWARE_WATCHPOINTS="y";
HAS_DMA="y";
HAS_IOMEM="y";
HAS_IOPORT_MAP="y";
I2C="y";
I2C_ALGOBIT="y";
I2C_BOARDINFO="y";
I2C_CHARDEV="y";
I2C_GPIO="y";
I2C_MT7621="y";
ICPLUS_PHY="y";
IRQCHIP="y";
IRQ_DOMAIN="y";
IRQ_DOMAIN_HIERARCHY="y";
IRQ_FORCED_THREADING="y";
IRQ_MIPS_CPU="y";
IRQ_WORK="y";
LIBFDT="y";
LOCK_DEBUGGING_SUPPORT="y";
LZO_COMPRESS="y";
LZO_DECOMPRESS="y";
MDIO_BUS="y";
MDIO_DEVICE="y";
MDIO_DEVRES="y";
MEDIATEK_GE_PHY="y";
MEMFD_CREATE="y";
MFD_SYSCON="y";
MIGRATION="y";
MIKROTIK="y";
MIKROTIK_RB_SYSFS="y";
MIPS="y";
MIPS_ASID_BITS="8";
MIPS_ASID_SHIFT="0";
MIPS_CLOCK_VSYSCALL="y";
MIPS_CM="y";
MIPS_CPC="y";
MIPS_CPS="y";
MIPS_CPU_SCACHE="y";
MIPS_GIC="y";
MIPS_L1_CACHE_SHIFT="5";
MIPS_LD_CAN_LINK_VDSO="y";
MIPS_MT="y";
MIPS_MT_FPAFF="y";
MIPS_MT_SMP="y";
MIPS_NR_CPU_NR_MAP="4";
MIPS_PERF_SHARED_TC_COUNTERS="y";
MIPS_SPRAM="y";
MODULES_USE_ELF_REL="y";
MTD_CMDLINE_PARTS="y";
MTD_NAND_CORE="y";
MTD_NAND_ECC="y";
MTD_NAND_ECC_SW_HAMMING="y";
MTD_NAND_MT7621="y";
MTD_NAND_MTK_BMT="y";
MTD_RAW_NAND="y";
MTD_ROUTERBOOT_PARTS="y";
MTD_SERCOMM_PARTS="y";
MTD_SPI_NOR="y";
MTD_SPLIT_FIT_FW="y";
MTD_SPLIT_MINOR_FW="y";
MTD_SPLIT_SEAMA_FW="y";
MTD_SPLIT_TPLINK_FW="y";
MTD_SPLIT_TRX_FW="y";
MTD_SPLIT_UIMAGE_FW="y";
MTD_UBI="y";
MTD_UBI_BEB_LIMIT="20";
MTD_UBI_BLOCK="y";
MTD_UBI_WL_THRESHOLD="4096";
MTD_VIRT_CONCAT="y";
NEED_DMA_MAP_STATE="y";
NET_DEVLINK="y";
NET_DSA="y";
NET_DSA_MT7530="y";
NET_DSA_MT7530_MDIO="y";
NET_DSA_TAG_MTK="y";
NET_FLOW_LIMIT="y";
NET_MEDIATEK_SOC="y";
NET_SELFTESTS="y";
NET_SWITCHDEV="y";
NET_VENDOR_MEDIATEK="y";
NO_HZ_COMMON="y";
NO_HZ_IDLE="y";
NR_CPUS="4";
NVMEM="y";
OF="y";
OF_ADDRESS="y";
OF_EARLY_FLATTREE="y";
OF_FLATTREE="y";
OF_GPIO="y";
OF_IRQ="y";
OF_KOBJ="y";
OF_MDIO="y";
PAGE_POOL="y";
PAGE_POOL_STATS="y";
PCI="y";
PCIE_MT7621="y";
PCI_DISABLE_COMMON_QUIRKS="y";
PCI_DOMAINS="y";
PCI_DOMAINS_GENERIC="y";
PCI_DRIVERS_GENERIC="y";
PCS_MTK_LYNXI="y";
PERF_USE_VMALLOC="y";
PGTABLE_LEVELS="2";
PHYLIB="y";
PHYLINK="y";
PHY_MT7621_PCI="y";
PINCTRL="y";
PINCTRL_AW9523="y";
PINCTRL_MT7621="y";
PINCTRL_RALINK="y";
PINCTRL_SX150X="y";
POWER_RESET="y";
POWER_RESET_GPIO="y";
POWER_SUPPLY="y";
PTP_1588_CLOCK_OPTIONAL="y";
QUEUED_RWLOCKS="y";
QUEUED_SPINLOCKS="y";
RALINK="y";
RATIONAL="y";
REGMAP="y";
REGMAP_I2C="y";
REGMAP_MMIO="y";
REGULATOR="y";
REGULATOR_FIXED_VOLTAGE="y";
RESET_CONTROLLER="y";
RFS_ACCEL="y";
RPS="y";
RTC_CLASS="y";
RTC_DRV_BQ32K="y";
RTC_DRV_PCF8563="y";
RTC_I2C_AND_SPI="y";
SCHED_SMT="y";
SERIAL_8250="y";
SERIAL_8250_CONSOLE="y";
SERIAL_8250_NR_UARTS="3";
SERIAL_8250_RUNTIME_UARTS="3";
SERIAL_MCTRL_GPIO="y";
SERIAL_OF_PLATFORM="y";
SGL_ALLOC="y";
SMP="y";
SMP_UP="y";
SOCK_RX_QUEUE_MAPPING="y";
SOC_BUS="y";
SOC_MT7621="y";
SPI="y";
SPI_MASTER="y";
SPI_MEM="y";
SPI_MT7621="y";
SRCU="y";
SWPHY="y";
SYNC_R4K="y";
SYSCTL_EXCEPTION_TRACE="y";
SYS_HAS_CPU_MIPS32_R1="y";
SYS_HAS_CPU_MIPS32_R2="y";
SYS_HAS_EARLY_PRINTK="y";
SYS_SUPPORTS_32BIT_KERNEL="y";
SYS_SUPPORTS_ARBIT_HZ="y";
SYS_SUPPORTS_HIGHMEM="y";
SYS_SUPPORTS_HOTPLUG_CPU="y";
SYS_SUPPORTS_LITTLE_ENDIAN="y";
SYS_SUPPORTS_MIPS16="y";
SYS_SUPPORTS_MIPS_CPS="y";
SYS_SUPPORTS_MULTITHREADING="y";
SYS_SUPPORTS_SCHED_SMT="y";
SYS_SUPPORTS_SMP="y";
SYS_SUPPORTS_ZBOOT="y";
TARGET_ISA_REV="2";
TICK_CPU_ACCOUNTING="y";
TIMER_OF="y";
TIMER_PROBE="y";
TREE_RCU="y";
TREE_SRCU="y";
UBIFS_FS="y";
USB_SUPPORT="y";
USE_OF="y";
WEAK_ORDERING="y";
XPS="y";
XXHASH="y";
ZLIB_DEFLATE="y";
ZLIB_INFLATE="y";
ZSTD_COMPRESS="y";
ZSTD_DECOMPRESS="y";
          } // lib.optionalAttrs (config.system.service ? watchdog) {
          RALINK_WDT = "y";  # watchdog
          MT7621_WDT = "y";  # or it might be this one
        };
        };
        boot = {
          commandLine = [ "console=ttyS0,115200" ];
          tftp = {
            #ipaddr = "10.0.0.8"; # router address
            #serverip = "10.0.0.1"; # build machine or other tftp server
            # Should be a segment of free RAM, where the tftp artifact
            # can be stored before unpacking it to the 'hardware.loadAddress'
            # The 'hardware.loadAddress' is 0x80001000, which suggests the
            # RAM would start at 0x8000000 and (being 128MB) go to
            # to 0x8800000. Let's put it at the 100MB mark at
            # 0x8000000+0x0640000=0x86400000
            loadAddress = lim.parseInt "0x86400000";
          };
        };
        filesystem =
        let inherit (pkgs.pseudofile) dir symlink;
             in
               dir {
                 lib = dir {
                   firmware = dir {
                     mediatek = symlink firmware;
                   };
                 };
               };

      hardware =
        let
          openwrt = pkgs.openwrt;
          mac80211 =  pkgs.mac80211.override {
            drivers = [
              "mt7615e"
              "mt7915e"
            ];
            klibBuild = config.system.outputs.kernel.modulesupport;
          };
        in {
          #ubi = {
          #  # TODO how to determine?
          #  minIOSize = "2048";
          #  # TODO how to determine?
          #  eraseBlockSize = "126976";
          #  # TODO how to determine?
          #  maxLEBcount = "1024"; # guessing
          #};
          # from OEM bootlog (openwrt wiki):
          # 4 cmdlinepart partitions found on MTD device raspi
          # Creating 4 MTD partitions on "raspi":
          # 0x000000000000-0x000000040000 : "uboot"
          # 0x000000040000-0x000000440000 : "uImage"
          # 0x000000440000-0x000000ff0000 : "rootfs"
          # 0x000000ff0000-0x000001000000 : "ART"
          # from openwrt bootlog (openwrt wiki):
          # 5 fixed-partitions partitions found on MTD device spi0.0
          # OF: Bad cell count for /palmbus@1e000000/spi@b00/flash@0/partitions
          # OF: Bad cell count for /palmbus@1e000000/spi@b00/flash@0/partitions
          # OF: Bad cell count for /palmbus@1e000000/spi@b00/flash@0/partitions
          # OF: Bad cell count for /palmbus@1e000000/spi@b00/flash@0/partitions
          # Creating 5 MTD partitions on "spi0.0":
          # 0x000000000000-0x000000040000 : "u-boot"
          # 0x000000040000-0x000000fa0000 : "firmware"
          # 2 uimage-fw partitions found on MTD device firmware
          # Creating 2 MTD partitions on "firmware":
          # 0x000000000000-0x0000002c0000 : "kernel"
          # 0x0000002c0000-0x000000f60000 : "rootfs"
          # mtd: setting mtd3 (rootfs) as root device
          # 1 squashfs-split partitions found on MTD device rootfs
          # 0x000000640000-0x000000f60000 : "rootfs_data"
          # 0x000000fa0000-0x000000fb0000 : "config"
          # 0x000000fb0000-0x000000ff0000 : "tplink"
          # 0x000000ff0000-0x000001000000 : "radio"
          flash = {
            # from the OEM bootlog 'Booting image at bc040000'
            # (0x40000 from 0xbc000000)
            address = lim.parseInt "0xbc040000";
            # 0x000000040000-0x000000fa0000
            size = lim.parseInt "0xf60000";
            # TODO how to determine?
            eraseBlockSize = 65536;
          };

          # since this is mentioned in the partition table as well?
          defaultOutput = "uimage";
          # taken from openwrt sysupgrade image:
          # openwrt-23.05.2-ramips-mt7621-tplink_archer-ax23-v1-squashfs-sysupgrade.bin: u-boot legacy uImage, MIPS OpenWrt Linux-5.15.137, Linux/MIPS, OS Kernel Image (lzma), 2797386 bytes, Tue Nov 14 13:38:11 2023, Load Address: 0X80001000, Entry Point: 0X80001000, Header CRC: 0X19F74C5B, Data CRC: 0XF685563C
          loadAddress = lim.parseInt "0x80001000";
          entryPoint = lim.parseInt "0x80001000";
          rootDevice = "ubi0:liminix";
          dts = {
            src = "${openwrt.src}/target/linux/ramips/dts/mt7621_tplink_archer-ax23-v1.dts";
            includes =  [
              "${openwrt.src}/target/linux/ramips/dts"
              "${config.system.outputs.kernel.modulesupport}/arch/arm64/boot/dts/mediatek/"
            ];
          };

          networkInterfaces =
            let
              inherit (config.system.service.network) link;
              inherit (config.system.service) bridge;
            in rec {
              lan1 = link.build { ifname = "lan1"; };
              lan2 = link.build { ifname = "lan2"; };
              lan3 = link.build { ifname = "lan3"; };
              lan4 = link.build { ifname = "lan4"; };

              wan = link.build {
                ifname = "wan";
                dependencies = [ mac80211 ];
              };
            };
        };
    };
    };
}