My symptoms were:
- Tivo lasted about 1-2 hours the first time (while in GSetup).
- Then, while going down long IR codes list started hanging,
- But would get a response once every ~2mins.
- If I didn't use it for e.g. ~10 minutes, then I could make ~5 button presses before hanging again.
- Unplugged power. Wait 1 minute. Plugged back in. RC Hang in about 1 min.
- Unplugged power. Plugged power back in. RC Hangs immediately.
- Unplugged power. Unplugged serial, LAN, IR. Plugged power back in. RC Hangs immediately.
- Tried connection by serial and rebooting. Still hangs immediately
- I felt around on the components. CPU was hot while functional but cooled down quick. But PSU transformer and heatsink stayed hot for quite a while.

So seems both "IR frequency of use" and "overheating - probably PSU" related.

or not... who knows.