Data Flash values after erase is "undefined" - Would LittleFS work?

[test-sg]

I would like to know if LittleFS is designed based on the assumption that, the values of flash after erase, are '0xFF'?
I am using a family of Renesas family MCU where the values of data flash after erase is 'undefined'

Would LittleFS work on this type of MCU?

[geky]

LittleFS doesn't assume 0xFF actually, so it should work.

To be exact, LittleFS requires only that subsequent reads after an erase returns the same value, or consistently returns LFS_ERR_CORRUPT.

Usually when flash devices say the value after an erase is undefined, it's because they include some extra error-correction that becomes invalid after an erase. But as long as it consistently reports invalid, we can use that to detect if the block has been erased.

But I would also double check the datasheet to see if they define "undefined". In theory a new storage type could put the storage into a truly unstable state on erase, but if that's the case I'm not sure it's even theoretically possible to log when power-loss is involved...

Worst case, erased-state in LittleFS is checked with a checksum before use, so if the erased-state is truly unstable it just means LittleFS will erase much more often. Though depending on the underlying storage this could be impractically slow.