Failed to build a Raspberry Pi image

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1

Hello,
I’m trying to build an image for a raspberry 2. To do so, I’ve written the following flake.nix (taken from a wiki)

{
  description = "Build image";
  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-25.05";
  outputs = { self, nixpkgs }: rec {
    nixosConfigurations.rpi2 = nixpkgs.lib.nixosSystem {
      modules = [
        "${nixpkgs}/nixos/modules/installer/sd-card/sd-image-raspberrypi.nix"
        {
          nixpkgs.config.allowUnsupportedSystem = true;
          nixpkgs.hostPlatform.system = "armv7l-linux";
          nixpkgs.buildPlatform.system = "x86_64-linux"; #If you build on x86 other wise changes this.
          # ... extra configs as above
          system.stateVersion = "25.05";
        }
      ];
    };
    images.rpi2 = nixosConfigurations.rpi2.config.system.build.sdImage;
  };
}

then nix build .#images.rpi2. However, this fails with

error: builder for '/nix/store/nwwa1z7h7hsypywxb9ybv2qjdryfi2rb-efivar-armv7l-unknown-linux-gnueabihf-39.drv' failed with exit code 2;
       last 25 log lines:
       >       |                                                                                  long unsigned int
       >       |                                                                                %llx
       >   364 |                                       iter->esl->signature_list_size,
       >   365 |                                       (intmax_t)(iter->len - iter->offset), iter->offset);
       >       |                                                                             ~~~~~~~~~~~~
       >       |                                                                                 |
       >       |                                                                                 off_t {aka long long int}
       > esl-iter.c:396:29: error: cast to pointer from integer of different size [8;;https://gcc.gnu.org/onlinedocs/gcc-14.2.0/gcc/Warning-Options.html#index-Wint-to-pointer-cast-Werror=int-to-pointer-cast8;;]
       >   396 |                 iter->esl = (efi_signature_list_t *)((intptr_t)iter->buf
       >       |                             ^
       > esl-iter.c:414:74: error: format '%lx' expects argument of type 'long unsigned int', but argument 4 has type 'off_t' {aka 'long long int'} [8;;https://gcc.gnu.org/onlinedocs/gcc-14.2.0/gcc/Warning-Options.html#index-Wformat-Werror=format=8;;]
       >   414 |                         warnx("correcting ESL size from %d to %jd at 0x%lx",
       >       |                                                                        ~~^
       >       |                                                                          |
       >       |                                                                          long unsigned int
       >       |                                                                        %llx
       >   415 |                               iter->esl->signature_list_size,
       >   416 |                               (intmax_t)(iter->len - iter->offset), iter->offset);
       >       |                                                                     ~~~~~~~~~~~~
       >       |                                                                         |
       >       |                                                                         off_t {aka long long int}
       > cc1: all warnings being treated as errors
       > make[1]: *** [/build/source/src/include/rules.mk:53: esl-iter.o] Error 1
       > make[1]: Leaving directory '/build/source/src'
       > make: *** [Makefile:17: all] Error 2
       For full logs, run 'nix log /nix/store/nwwa1z7h7hsypywxb9ybv2qjdryfi2rb-efivar-armv7l-unknown-linux-gnueabihf-39.drv'.

The full log is

armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -L.   -Wl,--build-id -Wl,--no-a>
ln -vfs libefiboot.so libefiboot.so.1
'libefiboot.so.1' -> 'libefiboot.so'
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
armv7l-unknown-linux-gnueabihf-gcc -Og  -g3 -Wall -Wextra  -Werror  -std=gnu11 -funsigned-char -fvisibility=hidden -specs=/build/source/src/include/gcc.specs -fno-merge-constants  -fPIC  -DLIBEFIVAR_VERSION=39 ->
esl-iter.c: In function 'esl_list_iter_next_with_size_correction':
esl-iter.c:338:80: error: format '%lx' expects argument of type 'long unsigned int', but argument 4 has type 'off_t' {aka 'long long int'} [-Werror=format=]
  338 |                                 warnx("correcting ESL size from %d to %jd at %lx",
      |                                                                              ~~^
      |                                                                                |
      |                                                                                long unsigned int
      |                                                                              %llx
  339 |                                       iter->esl->signature_list_size,
  340 |                                       (intmax_t)(iter->len - iter->offset), iter->offset);
      |                                                                             ~~~~~~~~~~~~
      |                                                                                 |
      |                                                                                 off_t {aka long long int}
esl-iter.c:363:82: error: format '%lx' expects argument of type 'long unsigned int', but argument 4 has type 'off_t' {aka 'long long int'} [-Werror=format=]
  363 |                                 warnx("correcting ESL size from %d to %jd at 0x%lx",
      |                                                                                ~~^
      |                                                                                  |
      |                                                                                  long unsigned int
      |                                                                                %llx
  364 |                                       iter->esl->signature_list_size,
  365 |                                       (intmax_t)(iter->len - iter->offset), iter->offset);
      |                                                                             ~~~~~~~~~~~~
      |                                                                                 |
      |                                                                                 off_t {aka long long int}
esl-iter.c:396:29: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
  396 |                 iter->esl = (efi_signature_list_t *)((intptr_t)iter->buf
      |                             ^
esl-iter.c:414:74: error: format '%lx' expects argument of type 'long unsigned int', but argument 4 has type 'off_t' {aka 'long long int'} [-Werror=format=]
  414 |                         warnx("correcting ESL size from %d to %jd at 0x%lx",
      |                                                                        ~~^
      |                                                                          |
      |                                                                          long unsigned int
      |                                                                        %llx
  415 |                               iter->esl->signature_list_size,
  416 |                               (intmax_t)(iter->len - iter->offset), iter->offset);
      |                                                                     ~~~~~~~~~~~~
      |                                                                         |
      |                                                                         off_t {aka long long int}
cc1: all warnings being treated as errors
make[1]: *** [/build/source/src/include/rules.mk:53: esl-iter.o] Error 1
make[1]: Leaving directory '/build/source/src'
make: *** [Makefile:17: all] Error 2

Does anyone have an idea on how to make it work?

2

My usual strategy with NixOS on RPi is to chop out anything which is tricky to build.

In this case, the package efivar gets installed from ${nixpkgs}/nixos/modules/profiles/base.nix, which is imported by sd-image-raspberrypi.nix.

We can remove efivar by chopping out the entire base.nix module:

{ modulesPath, ... }: {
  disabledModules = [ "${modulesPath}/profiles/base.nix" ];
}

Also it could be helpful to add the module ${nixpkgs}/nixos/modules/profiles/minimal.nix to your configuration. This will disable building things which aren’t usually necessary on a RPi, like documentation.

Another more surgical way of “removing” a package is through a nixpkgs overlay:

{
  nixpkgs.overlays = [ (final: prev: {
    efivar = final.emptyDirectory; # replace efivar with a dummy package
  }) ];
}

If your overlay will be used with other systems, then make your hacks conditional. Here is one of my overlays as an example:

final: prev: let
  inherit (final) lib;
  inherit (final.stdenv.hostPlatform) isAarch32;
  disableOnRpi = pkg: if isAarch32 then disabled else pkg;
  disabled = final.emptyDirectory;
  isCross = final.stdenv.buildPlatform != final.stdenv.hostPlatform;
in {
  # btrfs-progs fails to cross compile - disable it.
  btrfs-progs = if isCross then disabled else prev.btrfs-progs;
  # w3m fails to build on rpi - disable it.
  w3m-nographics = disableOnRpi prev.w3m-nographics;
}

You may encounter further build errors after this. Workarounds might be found in other Raspberry Pi threads on this forum, which can be found with a search.