Hello,
I'm using S25FL127S which does not support uniform 4k erase.
Library correctly reports via SFDP that flash chip does not supports uniform 4k erase, but it sets erase_gran and erase_gran_cmd to 4k erase anyway.
I modified library in such way that if sfdp.4k_erase is 0 then erase_gran and erase_gran_cmd is set to first eraser size which is larger than 4k, but I'm not sure if this is the correct way. I also dif not find any flags in SFDP that would tell which erase size is uniform for whole device.
Best regards