Hi Klaus, thanks again for taking the time to help with this. I've previously tried the pair/unpair commands, this is the output:

knoppix@Microknoppix:~$ idevicepair unpair
QueryType failed, error code -256
knoppix@Microknoppix:~$ idevicepair pair
QueryType failed, error code -256
knoppix@Microknoppix:~$ idevicepair validate
QueryType failed, error code -256