If you are installing a 69xx phone on an existing 53xx network you may have option 43 enabled on DHCP, this will stop your phone from contacting the MCS as its TFTP server and instead will contact he base server. To temporarily override this, go to the static network setting of the MiNet 69xx phone and enter the MCS address in the TFTP IP Address section and the IPA IP Address section, this will overide the DHCP setting until you can changed them.