Had a crash yesterday, also from nanov2_allocate_from_block, but this time from NSLog. Not sure of the exact cause.

Tried wrapping the save and open in a performAsynchronousFileAccessUsingBlock call and that appears to work! Not sure why no tutorials, the documentation or any forums mention it, but it works

Still need this, years later. Either this or an upgrade path from 12 to 14 for older hardware (but I doubt that is ever happening). Our customers cannot pay for new devices to replace working (older) hardware. It is too expensive and wasteful for them to justify.