bootparam "reboot=warm" needed on my UEFI system

[FeathersMcG]

Hi,

Not really a problem here, more of a solution that may be
of interest to others. With the UEFI64.img and RESCUE64.img
PBA images, my Intel NUC8i7hvk was power cycling much or
all of itself, including the NVME buses. Leading to a boot
loop into the MBR shadow.

I found that adding the "reboot=warm" bootparam to the
append line of EFI/boot/syslinux.cfg did the trick. Here are
the steps I took as root.

gunzip ./UEFI64.img.gz; losetup --find --show ./UEFI64.img

Assuming losetup created /dev/loop0,
change instance number if needed.

partprobe /dev/loop0; mount /dev/loop0p1 /mnt; cd /mnt/EFI/boot

Add "reboot=warm" to the line beginning with
"append" then save the file and exit the editor.

vi syslinux.cfg; cd; sync; umount /mnt; losetup -D

I'm not sure why I needed this bootparam. I checked my installed
Fedora 37 and noticed that /sys/kernel/reboot/mode is cold and
/sys/kernel/reboot/type is acpi but does not power cycle upon reboot.
Oh well, problem solved for me. Hope this helps others in need.

Best Wishes
Feathers

[vandrewal]

This was the exact info I needed, thank you! For some reason the PBA never seem to be able to boot directly into the OS after authentication (I would really like to know why this happens in the first place) and reboots, which causes a power cycle on my NUC as well.

Hopefully this can stay up in some form despite being the solution to an issue more than an actual issue. The instructions were very clear, and as an added bonus I now know how to edit .img files.

Thanks again!

[Blacklands]

For some reason the PBA never seem to be able to boot directly into the OS after authentication (I would really like to know why this happens in the first place) and reboots

I think this is just how it's implemented in this current PBA, for simplicity. Just rebooting is a lot simpler than trying to chainload into the OS bootloader. Especially since there's a bunch of different bootloaders.

[henriquebecker91]

Thank you a lot @FeathersMcG, I stumbled with the same problem (I was able to warm reboot from an Arch Linux in an non-encrypted disk, but the PBA reboots were always cold and locked the disks again). I was already thinking that I would need to have a pendrive with an arch installation with me at all times to be able to access my notebook, XD.

Added a section to the Arch Wiki about this: https://wiki.archlinux.org/title/Self-encrypting_drives#Troubleshooting:_PBA_Cold_Reboot_Locks_Drives_Again