grub's regexp does not change the store variable if there is no match,
so checking for empty variable after the regexp call was not really
working. Instead, check for successful regexp call.
This commit will help the boot speed on most PC devices and
requested by the Taipei team.
The changes to the auto-generated parts are done via:
```
$ cd boot/assets
$ go build -o ./genasset/genasset ./genasset/
$ ./genasset/genasset -in ./data/grub.cfg -out grub_cfg_asset.go -name grub.cfg
```
and the `Snapd-Boot-Config-Edition` for `grub.cfg` was bumped.
Note that no changes for the recovery grub configuration are done
in this commit. I'm happy to do a follwup for this.
* b/piboot.go: check EEPROM version for RPi4
Check EEPROM version for RPi4 to make sure that tryboot is
supported. If the EEPROM need updating, return an error when
installing the kernel.
* bootloader: add unit tests for detection of RPi4 EEPROM
* bootloader/piboot: use osutil instead of using directly os.Stat
* bootloader: address review comments
This is the same fix as commit 17fbdc7c, but in other tests.
The current code will mock the `amd64` architecture when running some
tests but it does not mock the `grub.cfg:static-cmdline` or the
`grub-recovery.cfg:static-cmdline`. This is needed because the
`bootloader/asserts` package registers the cmdline via `init()` so
this happens before the architecture is mocked in the testing
code. Hence the tests will fail when inspecting the command line on
non amd64/i386 machines.
This commit makes the mocking explicit. An alternative approach would
be to move the snippet registration out of `init()` and run it on
first boot but that has it's own problems so this other approach was
followed.
