I finally did a factory reset. It solved some issues, but not all:
Seems to be solved:
- Unstable applications (flashing and crashing, including Gmail).
- Unstable folders (flashing, crashing and all icons on the desktop disappearing).
- Wifi is unstable and does not auto-connect (I have to connect manually when I restart the tablet or when I get home... it was working fine before ICS).
- The GPS does not work (I am not sure if it was working before ICS... as I had not had the time to test, so maybe it is not new).
- System update does not work (indicates that network coverage is insufficient despite the signal being strong and staying beside the wireless router).