I have Firebird working on SME 5.5 U6:
[root@aguia root]# cat /etc/e-smith-release
Mitel Networks SME Server V5.5
[root@aguia root]# ps -ax|grep ibse
1346 ? S 6:52 /opt/interbase/bin/ibserver
1347 ? S 0:09 /opt/interbase/bin/ibserver
6568 ? S 0:00 /opt/interbase/bin/ibserver
6571 ? S 0:00 /opt/interbase/bin/ibserver
30897 ? S 0:06 /opt/interbase/bin/ibserver
31779 ? S 0:04 /opt/interbase/bin/ibserver
7118 pts/0 S 0:00 grep ibse
[root@aguia root]#
Never tried on 6.01-01... would it work as I read above.
I just was contacted by my client (aguia owner!) to do un upgrage on his server... including a FireBird upgrade to 1.5!
Shall I gracefully refuse the job?

Or just install 5.6 ... for now?
Thanks!
Jáder