I've pushed the fix for UAE filesystem to the winuae4200 branch
Turns out the problem what I had been too quick when porting
atomic_bit_test_and_reset
, and instead effectively implemented "atomic_bit_test_and_set" :-/
Fixed now
EDIT: Also continued merging 4.2.1 beta code, since 4.2.1 is going to be a minor bugfix release. Branch winuae4210
EDIT: Ported the fix "back in time" for the winuae4210 branch - and rewrote the git history - so that this corrected implementation is available when testing old winuae merge commits.