Good, I tell them.
I had a similar problem, I went out the warning icon next to the battery and not turn unless degas connected via USB or wall.
The way around this is to buy a new flex (where charge and plug the usb) sells full plate.
I got on ebay and bought a kit to disarm the cellular and change the board.
now, works great ...... from what I read, going on all S2 after a period of use.
if you want, I pass the link of felx I bought because if one trucho compraun, you might get in trouble!