Warning to all potential upgraders with 7940 or 7960 phones
We recently upgraded to Call Manager 12.5, all appeared ok but when a 7940 or 7960 rebooted it updated its firmware to SIP, an issue as all were set up as SCCP. Quickly 200+ of our 600+ phones were out of service.
We use extension mobility and SIP does not support this on CUCM 12.5, so reprogramming was not an option.
When monitored the phone reported it could not locate the SCCP load file so then upgraded to SIP.
It appears that on a CUCM v11 it just ignores this and kept its SCCP firmware. TFTP download confirmed the files were present.
Eventually it was discovered that if the phone has a number of services assigned to the phone it exceeds the 7940 & 7960 config file maximum size limit of 8k, we had about 7 subscribed services.
The missing file error is misleading, remove a couple of subscribed services and all works.
