AIV SCSI
Nothing at all. This is because SCSI drives change the SCSI ID with jumpers, and the BBC system can only understand devices on SCSI ID 0, even though there may be multiple drives on that ID, which are called logical units. As far as I know, there's no way to tell a SCSI disc to keep itself as ID 0 but become Logical Unit Number 1.
Having removed the jumper, we can access the disc as drive 0 again, but we get an error this time when trying to select drive 1.