Hi Alexander, my short search found some links that all say, UEFI cannot boot software AID. This makes much sense to me. The solution seems to have a /boot/efi partitions on each disk and have two UEFI boot entries.
https://askubuntu.com/questions/66637/can-the-efi-system-partition-be-raided https://outflux.net/blog/archives/2018/04/19/uefi-booting-and-raid1/ -- regards Thomas
