My Galaxy Nexus 4.2.2 won't show up as a MTP device anymore. It looks like the phone is the problem, I want to debug the problem from that end.

Like [many before me][1], I tried everything, and then some :

 - Using Ubuntu 13.04 or Windows 7, on 3 computers
 - Cleaning the USB port on the phone
 - Using the original cables
 - Reboot with or without the cable, with or without the SIM card
 - Removing the battery all night (after shutting down the phone) to clear *everything* from memory
 - Uninstalling Google Play Music (I only use MTP to sync music)

I also have a second phone that shows up as a MTP device and syncs just fine. It is also a Galaxy Nexus running 4.2.2. Neither of them are rooted. So I think the phone must be the problem.

How can I troubleshoot or debug MTP problems **on the phone** ?



  [1]: http://android.stackexchange.com/q/35635/12736