* We are experiencing some interesting issues with some of our older legacy devices, primarily around their bootloader.
We have been debugging for some time, and have now managed to narrow it down to our swap state getting corrupted mid swap.
If we look at the swap section (7 pages of 2K) just after an erase operation, we see single bits not being erased?! 

The position seems random within this section, but it seems like it is always just a single bit (values of 0x7f, 0xf7 etc)
ST claims at least 10K program/erase cycles, and we are fairly sure we are nowhere near that, but could this sound like anything other than flash wear?

MCU is STM32L475