Hello 
Yesterday I wanted to prepare to update proxmox from version 7.x to 8.x. After running the pve7to8 command, a warning appeared to install the grub-efi-amd64 package, so ok, I installed it and just to be on the safe side, I restarted the server. After that, the server did not get up again and stayed in grub rescue with the error "error symbol grub_is_lockdown not found". Even the grub menu with kernel selection doesn't show up.
Going further, I managed to turn on the server via a pendrive with the Proxmox installation and selecting "Rescue boot", I thought that maybe updating to version 8.x would help with this problem and fix grub, the update went fine, almost without any problems, but it did not fix it to boot the server. Also, to run Proxmox I have to boot it from a pendrive. Can anyone help, or is it just a matter of wiping the disk and installing everything from scratch (I would like to avoid this)?
Yesterday I wanted to prepare to update proxmox from version 7.x to 8.x. After running the pve7to8 command, a warning appeared to install the grub-efi-amd64 package, so ok, I installed it and just to be on the safe side, I restarted the server. After that, the server did not get up again and stayed in grub rescue with the error "error symbol grub_is_lockdown not found". Even the grub menu with kernel selection doesn't show up.
Going further, I managed to turn on the server via a pendrive with the Proxmox installation and selecting "Rescue boot", I thought that maybe updating to version 8.x would help with this problem and fix grub, the update went fine, almost without any problems, but it did not fix it to boot the server. Also, to run Proxmox I have to boot it from a pendrive. Can anyone help, or is it just a matter of wiping the disk and installing everything from scratch (I would like to avoid this)?