First are you running the phones as SIP phones or as Mitel IP phones? Do you have a TFTP server setup with the software for the phone that it needs to download on boot is DHCP passing the file name Option 67 in DHCP? Do you have the IP address of the TFTP server set in DHCP as option 66? Option 129 RTC should be the IP address of the IP Gateway, oh and also I beleive you need option 125 setup as an ascii string "id:ipphone.mitel.com;sw_tftp=192.168.1.1;call_srv=192.168.1.1;vlan=1;l2p=6;dscp=46" of course insert your own IP address that is just and example.

If you can't Dazzle them with Brilliance. . . Confuse them with BS