Fixes error
Can't use an undefined value as an ARRAY reference at /nix/store/...-install-grub.pl line 642, <FILE> line 5.
with `/boot/grub/state` being:
```
grub
2.04
no
/dev/sda
/boot
```
I am not sure where the trailing empty line can come from; the script does not
seem to write it. In any case, now we handle that situation as well.
Further, ensure that `extraGrubInstallArgs` defaults to the empty array
if its key is not present in the `jsonState`.
For example, turns the error
cannot copy /nix/store/g24xsmmsz46hzi6whv7qwwn17myn3jfq-grub-2.04/share/grub/unicode.pf2 to /boot
into the more useful
cannot copy /nix/store/g24xsmmsz46hzi6whv7qwwn17myn3jfq-grub-2.04/share/grub/unicode.pf2 to /boot: Read-only file system
Useful for when you need to build grub modules into your grub kernel
to get a working boot, as shown in the added example.
To store this new value, we switch to more structural JSON approach.
Using one line per value to store in `/boot/grub/state` gets really messy when
the values are arrays, or even worse, can contain newlines (escaping would be
needed). Further, removing a value from the file would get extra messy
(empty lines we'd have to keep for backwards compatibility).
Thus, from now on we use JSON to store all values we'll need in the future.
This can be used to explicitly specify a specific dtb file, relative to
the dtb base.
Update the generic-extlinux-compatible module to make use of this option.
Some bootloaders might not properly detect the model.
If the specific model is known by configuration, provide a way to
explicitly point to a specific dtb in the extlinux.conf.
This option exposes the builder command used to populate an image,
honoring all options except the -c <path-to-default-configuration>
argument.
Useful to have for sdImage.populateRootCommands.
Special care needs to be taken w.r.t cross - the populate command runs
on the host platform, the activation script on the build platform (so
the builders differ)
The way this ends up being called with the raspberry pi 4 image builder
ends up not using the `-e` from the shebang.
In turn, the builds fails during cross-compilation. The wrong coreutils
ends up being used, but this is not made apparent.
The issue I faced is already fixed on master, but this ensures no one
ends up with a failed build "succeeding".
Memtest86+ doesn't support EFI, so unfree Memtest86 is used when EFI
support is enabled (systemd-boot currently also uses Memtest86 when
memtest is enabled).
A centralized list for these renames is not good because:
- It breaks disabledModules for modules that have a rename defined
- Adding/removing renames for a module means having to find them in the
central file
- Merge conflicts due to multiple people editing the central file
Add support for custom device-tree files, and applying overlays to them.
This is useful for supporting non-discoverable hardware, such as sensors
attached to GPIO pins on a Raspberry Pi.
