What might cause mDot SPI flash corruption and how can it be avoided?

There was a change in the 2.0.16 firmware that monitored for low voltage that would stop allowing writes to the SPI flash, but the bigger issue might be multi-threaded attempts to write to the SPI flash. The 3.0.0 and older firmware didn't handle multi-threaded writes to SPI flash, so it was found to be easy to corrupt the SPI flash as a result of several threads trying to write at the same time. A newer version of the 3.x firmware should be coming soon, but until then customers may use the latest mDot dev library with Mbed OS 5.5.7. The latest mDot library has the fix for the multi-threaded SPI flash access.