Hi,
Yes I followed the exact link you mention.
The system is my home lab so its i3 4330T with Asus B85M-E mobo.
Its EFI installation with RAID 1 on ZFS.
Unfortunately this system also run router for my home network so I had to act quick and make fresh install of Proxmox 6.2.
Never the less it would be great to know what to do if such situaion happens in the future.