Some code used from Retrodrive.bt but separated for better readability, dir_clust_sz gets calculated automatically, also different first tracks (with different sectors/track) are no problem anymore, Imagesize which are not a multiple of 256 (corrupted) get read fine usually, Possibility to override the automatically found values for the first track, Partially deleted files in the rootdir get flaged as --FREE-- if first character of FileName is zero or 0xFF or FirstTrack is zero.
