Not to thread jack but I have a similar problem and instead of opening a new thread I decided to revive this one.
I have a similar problem that my TF101 has been working flawlessly for many years. It is rooted and was running 4.3 ROM. As of yesterday, it just won't boot at all. It has been stuck at the NVidia screen and just sits there. I tried to enter recovery mode by using volume(-) + power and the unit presents the TWRP logo and just loops as well by showing the TWRP screen (3 seconds) then going blank for a second then showing TWRP screen again in a cycle. I downloaded and tried Easyflasher and Brks toolkit and nothing can complete the flash. I can enter MTP mode which the computer can see the device but the manufacturer name and model are not-recognized. I can also enter APX mode but while trying to flash anything I get an error message (error, cannot flash bootloader) and the computer dings (device disconnects).
I have been trying for a day now and have run out of ideas.
Has the unit finally bit the dust? Does any one out there have any more ideas or suggestions on what to try next?
TIA for any help provided.