Engineering solutions
There are a number of potential fixes that don't involve a garage visit, it is just an engineering problem.
Firstly, reduce the amount of information you "need" to store to an absolute minumum, this always helps.
If the unit has permanent power, you could keep this in RAM, and only commit to flash if the battery is disconnected, relying on your bulk capacitors. However there are a number of tricky issues involved, many of which could be overcome, but it's all a lot of work. Things like the latency between detecting loss of power - perhaps the unit might be asleep? - and getting on with the write. You may only be able to write a few blocks, depending on the write time and your capacitance.
Best then to have an acceptable "no data saved" backup configuration.
My preferred solution, assuming there is no other easy fix, is to make the nVidia chip so it never writes its flash again - and offload the NVM storage either to another unit on the CAN bus, existing or new, or even, ghastly but cheap, make a device that plugs into the OBD port, and store stuff on there.
Biting the hand that feeds IT
