I know, Leap 15.5 is end of life.
That is the reason for looking for the ability to boot either Leap 15.5 or 15.6 during the transfer phase.
Within 15.5 I created a new partition (type: Linux filesystem) and copied the contents of the root filesystem from openSUSE-Leap-15.6-ARM-KDE-raspberrypi.aarch64-2025.01.29-Build15.31.raw to the new partition.
Then I created a new grub.cfg via YAST and selected “Probe Foreign OS”.
The following reboot offered also Leap 15.6 but it failed to boot.
Rebooted 15.5 and replaced /boot/efi with the contents of the EFI filesystem from openSUSE…31.raw.
Reboot loaded Leap 15.6 successful.
I again created a new grub.cfg like above.
The following reboot offered also Leap 15.5 but it failed to boot.
How can I manage to be able to boot Leap 15.5 AND 15.6 from the same EFI partition?
Regards
Sorry!
I did a typo! I’m talking about Raspberry Pi 4
Sorry!
(I was not allowed to edit my post.)
@ifswirth Hi, likely it’s over writing the /boot/efi/opensuse info, you have to go into the respective /etc/default/grub entry and change the distributor entry on one of the systems eg leap155 and it will create a /boot/efi/leap155 directory for the boot loader contents…
@malcolmlewis Thanks, but there is no /boot/efi/opensuse.
Remember, it’s Raspberry Pi 4 which does not have a real UEFI.
There is only “/boot/efi/EFI/Boot”.
But I will try.
@malcolmlewis I tried and it failed.
Standard UEFI entry is “/boot/efi/EFI/{||opensuse}”.
This is also NOT created.
That doesn’t surprise me. There’s no real UEFI BIOS at the Pi 4.
Any other hint?
regards
Only one bootloader is required per computer. Why not be content to use only the 15.6 bootloader, and disable or remove that installed on 15.5?
I know, Leap 15.5 is end of life.
Check your system backup and then upgrade your Raspi4 to Leap 15.6. Follow the instructions in chapter “12.1.4 Distribution upgrade with Zypper”:
Or prepare a replacement micro sd card with Leap 15.6…
@mrmazda
I would like to use only the 15.6 bootloader, but it does not boot the 15.5 entry in grub. 
@GrandDixence2
I need during the transfer phase both versions.
An inplace upgrade would install the 15.6 EFI part which does not boot the 15.5 entry of grub.
I want to do a fresh install in a new partition to get rid of unneeded things I collected.
I’ll have a look into your GitHub hint.
Regards
So let’s find out why and fix it, unless there’s something very different about booting raspi4 that prevents it. Does /etc/default/grub exist and contain ‘GRUB_DISABLE_OS_PROBER=“true”’?
In Grub for x86, a stanza one knows works in 15.5’s own Grub could be copied into an optional file /boot/grub2/custom.cfg, which 15.6’s Grub would add to its own menu. The copy might need a bit of editing to work. I make my own from scratch, but custom.cfg is in routine use here on every UEFI PC. Here’s an example:
menuentry "openSUSE 15.5 defkernel 3 on P21" {
load_video
set gfxpayload=keep
search --no-floppy --set=root --hint-efi=hd0,gpt21 --label <filtered>
linux /boot/vmlinuz root=LABEL=<filtered> noresume preempt=full mitigations=off
initrd /boot/initrd
}
Repeating “it does not work” over and over again is not useful Show grub configuration (starting with what you have in \EFI\Boot). Describe what happens - what you see on the screen, what (error) messages are displayed, what do you do, at which point it “fails to boot”.
Sorry for the delay.
I crashed my EFI partition. EFI/fat is case INSENSITIVE.
I didn’t pay attention to that and therefore deleted everything.
I’ll recover from the install media.
I’ll come back.
After I accidentally crashed my EFI partition, I recreated it from the image above.
Now I can boot 15.6 or 15.5 out of grub2.
Both run well.
This solves my main problem.
Obviously I mixed up EFI 15.5 and 15.6 in my attempts.
There’s still an issue left with different behavior between cold and warm boot.
I’ll open a new case for that.
Thanks and regards