I went ahead and installed the system.
At first I did not realize that there was an EFI System Partition type and I used vfat instead (as in my laptop the mount command shows it as vfat), but the installer refused to use vfat. So I realized I should have used the EFI System Partition and I managed to complete the installation.
This is something that should be documented IMO. Not sure where…
Now I tried booting the installed system, but there’s some problem. I see this error:
error: ../../grub-core/kern/fs.c:120: unknown filesystem.
Entering rescue mode...
grub rescue>