Journalling (?) single-block parameter storage

[MikeW]

Any prior art ?

I have a single eraseblock available, and the need to store an
updateable (small, 20-30 bytes) parameter block which is fixed in size.

Although I can easily come up with a sequential block-invalidating storage
scheme, eventually erasing the block when the end is reached, I wondered
whether anyone knew of an existing library package which would achieve
these ends.

Searching brings up lots of stuff on flash filesystems, but nothing on
such a simplified requirement.

Regards,
MikeW