try a reflow of the amtels m8 on the mainboard and the chips on the sim and try a different sim if ya can get ya hands on one wether its from a 1010 or 1000
can you get into the eng menu and do a force download still?
With a soldering iron, solder and flux if your a pro with a soldering iron, or an expensive iron with correct attachments. Or diy it with a hairdryer lol.