I randomly run into the phone starts a reboot loop when incoming calls occur. The phone starts to ring then it reboots (grandstream logo screen and all) then the phone starts ringing again and when you try to answer it reboots again. After this occurs within 5 minutes the phone will register a missed call but when you try to check the missed call the phone locks up and reboots a couple more times.
This has happened on three occasions today and I am on the current 188.8.131.52 firmware. Two calls were internal from other extensions on my UCM6104 and the third was an incoming call to the UCM from a POTs line on one of the the UCM FXO ports.