Format as vfat fails with error: Device busy

[SimonBard]

I am following the docs here

But I fail at step 4: Install zfsbootmenu

How to do this? I followed along here:

# efibootmgr -c -d "$BOOT_DISK" -p "$BOOT_PART" \
>   -L "ZFSBootMenu (Backup)" \
>   -l '\EFI\ZBM\VMLINUZ-BACKUP.EFI'
invalid numeric value

I guess I need to adapt it, but dont know how. I am not familiar with raid systems and not with mdadm

I would guess like this:

efibootmgr -c -d "/dev/md/esp" \
  -L "ZFSBootMenu (Backup)" \
  -l '\EFI\ZBM\VMLINUZ-BACKUP.EFI'
  
  
efibootmgr -c -d "/dev/md/esp" \
  -L "ZFSBootMenu" \
  -l '\EFI\ZBM\VMLINUZ.EFI'

[classabbyamp]

If adding boot entries with efibootmgr, add entries for each disk in the mdraid array.

the efi firmware will not care about the raid

[SimonBard]

So this would mean

# efibootmgr -c -d "sda" -p "1" \
>   -L "ZFSBootMenu (Backup)" \
>   -l '\EFI\ZBM\VMLINUZ-BACKUP.EFI'

But this returned
invalid numeric value

I tried like I stated above in the first post, but now none of the HDD/SSD starts. I have to startover anyhow.

[classabbyamp]

-d /dev/sda