can’t mirror boot pool EZFS_BADTARGET

[ccdff]

I’m finally mirroring my boot-pool! Well at least I’m trying. I followed the guide: https://www.truenas.com/docs/core/coretutorials/systemconfiguration/mirroringthebootpool/
but I’m getting the following error:

I don’t mind using zpool, but before I get my hands dirty I just want to make sure I’m not missing something. Tried it with multiple drives.

toodles