We have a large quantity of 7900 series phones that we are going to dispose of and I need to know how to take them down to "fresh out of the box" configuration. I've tried factory resets while connected to a configured network port, a defaulted port, and with using an external power supply. None of these methods have resulted in a device with our network information removed. Any assistance resolving this would be greatly appreciated.
A factory reset should do exactly that, are you sure you're not getting an IP via DHCP and that's what you're seeing?
What models and what is the exact procedure you're following?
DHCP would definitely be the reason I'm still getting the network info back on the phones. I'm trying to wipe 7945s and 7965s. My first method was a factory reset while connected to a switch port configured for a phone, then resetting after removing the voice vlan. When neither worked, I just tried a factory reset using an external power supply and that didn't work. Since my networking knowledge is still pretty limited I ran out of ideas rather quickly and threw up the white flag.
Okay, I've just tried a factory reset again with a 7965 connected to a switch port with only the access vlan, no voice vlan or anything else voice-related. The phone now alternates between the initial boot-up screen and the one that comes up when a phone is upgrading. It doesn't have any firmware listed in the box. Is it safe to assume that if this phone is connected to a different entity's network all of our information will be deleted?