initramfs selection broken when kernel=kernel8.img #1965

Describe the bug

Something is broken in initramfs loading with kernel=kernel8.img on a Pi5, such that the wrong initramfs is loaded.

Steps to reproduce the behaviour

• Boot a Pi5 with the normal kernel. Add break=premount to /boot/firmware/cmdline.txt
• Reboot and the system will stop in initramfs
• Observe that the output from lsmod displays a few modules that have already been loaded
• exit initramfs and the system will continue booting
• Edit /boot/firmware/config.txt
  • Add kernel=kernel8.img
• Shutdown and reboot into initramfs
• Observe that the output from lsmod displays only the listing header and NO modules
• exit initramfs and the system will continue booting
• Edit /boot/firmware/config.txt
  • Comment out auto_initramfs=1
  • Add initramfs initramfs8 followkernel
• Shutdown and reboot init initramfs
• Observe that the output from lsmod works again, showing loaded modules

While this is not a problem in the normal use case, trying to use cryptsetup in initramfs fails due to the incorrect initramfs being loaded.

See https://gitlab.com/cryptsetup/cryptsetup/-/issues/940 for additional details and comments from the cryptsetup developer, Milan Broz.

Device (s)

Raspberry Pi 5

System

https://pastebin.com/UEh3iz2h

Logs

No response

Additional context

No response