Is there a way to go back to a stock 504G firmware coming from a UC320W?

[dalleybrent]

Our UC320W has been flakey for a bit now and it has been EOL for awhile. Our phones though still work perfectly fine. I went to upgrade to a new firmware and found out the UC320W put custom firmware on the phones and they don't seem to have a simple upgrade path to newer firmware. 

If I try to upgrade to 7.5.2b the phone screen does say its upgrading the firmware but then doesn't change anything and stays at the UC320W firmware. Even out of some desperation, I tried downgrading to an earlier version of the firmware then what the UC320W has with the same results.

I did go searching the forum for some answers but didn't see anything. It would be awful to have a perfectly good working phone be bricked by using a cisco PBX. 

[Dan Lukes]

No "UC320W custom firmware for SPA504G phone" exists, as far as I know. Yes, UC320W push firmware to phone, but it's standard firmware.

Unless you upgraded UC320W firmware, there's no reason do downgrade/upgrade SPA504G. Particular UC320W version works with particular SPA504G version only.

You mentioned neither current nor intended new version of SPA504G, also, reason for upgrade remain undisclosed. Sorry, so hard to advise something valuable ...