I had to go yesterday and today to replace a UC500 that had crashed. I think it was electrical related, but because another engineer started all of this, Im not sure what really happened. When I got onsite yesterday, I put the new system in and the 7960s and 7940s booted up just fine, but the 521s and the 524s did not. Actually, only about 4 of the 521s did boot up, the rest of the phones had the message that showed up on the screen during boot:
cp524g-08-01-07.bin. On those 521s that did boot up, they had firmware version cp524g-8-1-17.bin. Interestingly, that is what caused these phones to boot up. I ended up finding that firmware again and putting it on the new UC500 compact flash and the phones came up. Now, this did take some time to troubleshoot to find the problem. I never would have thought the firmware would show this message. Even more interesting to this issue, was that if you did an auto discover, and then set the button command on the ephone, it would come back to this message with that 8-1-07 firmware. Very odd. Ive seen odd things with firmware before, but not like this one.
By the way, Cisco says the no longer support the 521s and 524s. Therefore, I couldn't get the firmware from them. Its not on their download site either.
Anyway, after getting the system back up, I had to create the voicemail, auto attendant, and integration with the Bogan paging again. It took some time, but all is good again.