The device would not actually do any attempt to install a firmware that doesn’t match the type of the device model. So it should be enough to create the correct phone model configuration in CM and then let the device start the registration process from the beginning to make it register with CM.
On your question as such, this is how you do a hardware reset of a Cisco phone.
https://m.youtube.com/watch?v=auce4I4Lpao
@bstrubeTD3 wrote:
This is a factory reset. This is not what I want, as I specified in my message. I need to do a hard reset and reset everything in the phone.
This will do that. There are no other option for reset.
On the 79XX there was also another reset sequence, 3491672850*#. You could test is that makes any difference, or even work on the newer phones, for you as I assume that you have used the normal reset sequence and it doesn't do what you want it to do.
Option 1
Pull the network cord out of the phone and plug it back in (physically resetting the unit)
Immediately press and hold the # key and while the Headset, Mute, and Speaker buttons begin to flash in sequence, release the # key (you may have to hold the # for 30 seconds).
Press 123456789*0# after the line lights buttons will begin to flash in sequence (you only have 60 seconds to do this, then it goes back to normal booting).
If you’ve done it right you’ll see the phrase “Upgrading”
Option 2 (if option 1 doesn’t work)
Power off the phone (if using inline power, just remove the ethernet).
Hold the # key down.
Power on the phone while still holding down the # key.
When the line buttons scroll down orange, you can take your finger off the hash button
Press the following buttons: 3491672850*#
The line buttons should continue to scroll, but now they should be red
After about 60sec, this will change to green, and the phone should the boot up correctlyThe text is from this page Reset a Cisco phone to factory defaults
