I had the same problem. Fixed it with a bootable USB-Stick where Proxmox was installed in EFI Mode.
I installed Proxmox from a USB boot medium to another 15 GB USB stick. Unfortunately this doesn't work to boot the original system.
The boot process always ends in an initramfs console.
The drives sda, sdb and sdc are the previous ZFS installation. The drive sde is the Proxmox installation stick. The drive sdd2 will become the new boot drive.
findmnt /
zpool import -f -R /mnt rpool
mount -o rbind /proc /mnt/proc
mount -o rbind /sys /mnt/sys
mount -o rbind /dev /mnt/dev
mount -o rbind /run /mnt/run
chroot /mnt /bin/bash
proxmox-boot-tool format /dev/sdd2 --force
proxmox-boot-tool init /dev/sdd2
proxmox-boot-tool clean
proxmox-boot-tool status
The boot process always ends in an initramfs console. Here I can do a
zpool import -f rpool
However, the boot process still stops at initramfs.
When I When I press CTRL + D after rebooting I get this message:
What am I doing wrong?
Thank you
tony