ZFS replacing drive issues

[Da Rock]

I haven't seen anything specifically on this when googling, but I'm 
having a strange issue in replacing a degraded drive in ZFS.

The drive has been REMOVED from ZFS pool, and so I ran 'zpool replace 
<pool> <old device> <new device>'. This normally just works, and I have 
checked that I have removed the correct drive via serial number.

After resilvering, it still shows that it is in a degraded state, and 
that the old and the new drive have been REMOVED.

No matter what I do, I can't seem to get the zfs system online and in a 
good state.

I'm running a raidz1 on 9.1 and zfs is v28.

Cheers