Option partition not allowed for pmbootstrap flasher flash_kernel

Describe your issue

What's the expected behaviour?

Flashing the kernel to device without any issue

What's the current behaviour?

Sending 'boot' (7404 KB)                           OKAY [  0.205s]
Writing 'boot'                                     FAILED (remote: 'This partition doesn't exist')
fastboot: error: Command failed

How to reproduce your issue?

pmbootstrap flasher flash_kernel

What device are you using?

amazon-biscuit

On what postmarketOS version did you encounter the issue?

• edge (master branch)

• v24.12

• v24.06 (supported until 2025-01-23)

• I confirm that the issue still is present after running sudo apk upgrade -a

On what environment did you encounter the issue?

Environments

• GNOME Shell on Mobile
• Phosh
• Plasma Mobile
• Sxmo (Wayland/Sway) Please post the output of sxmo_version.sh
• Other: Please fill out

Which init system are you using?

• OpenRC
• systemd

How did you get postmarketOS image?

• from https://images.postmarketos.org
• I built it using pmbootstrap
• It was preinstalled on my device

Additional information

Hi there, I'm pretty new to postmarketOS, so I'm not sure if that is really an issue.

I tried to execute pmbootstrap flasher flash_kernel, to flash the kernel to amazon-biscuit. I got the following error:

[18:12:18] (native) flash kernel amazon-biscuit
[18:12:20] (native) install android-tools
Warning: skip copying boot image avb footer (boot partition size: 0, boot image size: 7581696).
Sending 'boot' (7404 KB)                           OKAY [  0.205s]
Writing 'boot'                                     FAILED (remote: 'This partition doesn't exist')
fastboot: error: Command failed

After a bit of digging, I came to the conclusion, that this is expected, as the device has as default the partitions "boot_a" and "boot_b" - depending which slot is active. Therefore I tried to execute pmbootstrap flasher flash_kernel --partition=boot_b as kinda stated here for rootfs. I got the same error.

I finally changed the default-value in variables.py to boot_b. I noticed, that you may change deviceinfo_flash_fastboot_partition_kernel - however, it may also be allowed to use --partition=boot_b as the active slot may vary.