Could you try the attached core, and let me know if it solves this issue, please?
(I found a bug which I'd introduced into the bookmark code, which basically disabled the bookmarks. There's still a weird memory corruption / ROM loading issue which only appears to affect V2 hardware - still investigating that...)
Good work, it indeed solved issue, many thanks I tried with my older SD-card, which has 16k cluster size. There was no more problems loading directories, and saving worked as in earlier core "20230328".
Tested with Turbo Chameleon v1 standalone.