Ok, with corrupted memory I don't mean the area where you store data, but the Ram installed.
There have been quite a few reports lately that the new TT devices fail due to cheap components used, similar story to the problems some flat screen producers had.
The BL basically only controls the USB transfer, most internal functions are too similar to be affected by it.
If you check Ebay you'll find lots of TT's with the red cross problem, sometimes even the same device several times over the months as it changes the owners LOL
There is only one trick that might! be of use:
Don't set the time, but instead get the latest quick fix first and let the device get a sat lock so you calculate a route.
If that works you can still try to set the time, if it fails you know for sure you got a hardware problem.
If you check the turoials onhow to add a SD to older models without a slot you can find posts that show direct connections to the main chip on the board.
So I'm almost certain it would be possible to find the point to read the TT with a flash tool, but I don't see the use in it.
With a correct NC and map a TT will always boot and work, if not (and the installation is indeed correct) there must be a hardware fault, especially if the same problem happens at the same stage with different NC's.
I simply assume you followed the correct procedure and did a hard reset followed by the TT clear Flash tool before starting a new NC? This makes sure you don't run into trouble cause by leftovers of the old installation (in the persistant Ram sections).