Datakanja de Bruyn wrote: ... > 1. bullseye installer had installed grub2 over refind, thereby killing > my setup made for safety purpose.
some of this may not fit your system, but it may help get you further in the ballpark. :) here are my notes and suggestions from previous events: if grub gets reinstalled it can remove or mess up the boot menu so the following command will recreate the entry if it has been deleted: # efibootmgr -c -L Debian_Refind -l "\EFI\BOOT\BOOTX64.EFI" this shows the current setup: # efibootmgr BootCurrent: 0001 Timeout: 1 seconds BootOrder: 0001,0000,0006,0007,0005 Boot0000* Debian_Refind Boot0001* debian Boot0005* ASUS DVD-E818AAT a Boot0006* Samsung SSD 850 EVO 500GB Boot0007* Samsung SSD 860 EVO 2TB this sets the boot order: # efibootmgr -o 0,1,5,6,7 BootCurrent: 0001 Timeout: 1 seconds BootOrder: 0000,0001,0005,0006,0007 Boot0000* Debian_Refind Boot0001* debian Boot0005* ASUS DVD-E818AAT a Boot0006* Samsung SSD 850 EVO 500GB Boot0007* Samsung SSD 860 EVO 2TB If reinstalling grub gets rid of your 40_custom menu entry this will work: you may need to change where the root is in the script below using the file /etc/grub.d/40_custom replace it with: ===== #!/bin/sh exec tail -n +3 $0 # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. # menuentry "Refind Menu" { insmod part_gpt insmod fat insmod chain root=hd0,1 chainloader /EFI/BOOT/BOOTX64.EFI } ===== > 2. Also, when i tried to boot into the oldstable by hand, it failed to > come up due to some error in fstab, bcoz the installer, while > reformatting the free partition, assigned a new partuuid to it, which no > longer corresponded to the entry in fstab. yes. it may also set up a new swap partition. > 3. Furthermore, it installed a grub2 version, that is buggy and which > cannot boot the bootentries, i was used to resort to in case of trouble > (a.k.a. booting straight from an ISO image as an emergency system. The > version installed was known to fail to boot on my kind of hardwae since > several years, and i assumed (my mistake), that a stable debian would > have been fixing the issue by now. (I refer to the links at the bottom). > > Ok. After days in panic, i was able to straigthen out my old system and > get it to boot again. But since then, i am totally undecided (and a bit > overwhelmed) with the options, i have to decide about now. What shall i > focus on next? see if you can fix the UEFI setup and add the other thing above to give you a way to get back to refind even if grub gets installed by accident again. i've had to use the above efibootmgr a few times. > 1. Try the whole process once again and manually downgrade grub2 in > order to have the ISO-boot at hand? (What risk would that involve?) > 2. Report a bug (but honestly, i am not skilled enough to even determine > the package(s) causing the mess i encountered. I suspect at least one of > grub2 packages to be involved, but also the installer itself does a > pretty careless job IMHO. (I learned to create proper assertion checks > before shooting a working configuration to death.) > 3. Continue to work with oldstable, which increasingly causes problems > due to the outdated software involved. That is, what i am using right now= >=2E > > Or is there a better option? - Like maybe someone willing to assist in > the process or at least guiding me some steps further? > But i am scared to show the details of what i am doing, as i am a ZFS > user since many years, which is pretty much non-standard! > > The bug, i mentioned seems to be related to grub2 2.04 and UEFI booting, > which is necessary on my machine: > https://superuser.com/questions/755641/grub2-boot-error-out-of-memory > https://bugzilla.redhat.com/show_bug.cgi?id=3D1838633 > https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1851311 > https://ubuntuforums.org/showthread.php?t=3D2430437 > > Any hint will be greatly appreciated. > DdB hopefully what i've provided above will help. i don't use ZFS myself. i try to keep thing simple. but i do dual boot stable and testing/unstable and also have both grub and refind installed. songbird