I ASS-u-me-d the system would not boot further because of the changes in ROM and the superdrive floppy driver present. I also stated not too long ago that I had compiled GSport to not put in any patches to the ROM. Well, guess what - when I launched the modified GSport with my Twain ROM the damn thing booted !!! I then used my new checksum routine I just posted to calculate a checksum 'tweak'. It came back with $9B3D. I put that into the Twain hex file at $3FFF6 and now the Twain ROM passes diagnostics !!! This just gets better !!! I tried to insert an 800k floppy and as expected, it reports it doesn't recognize it and wants to initialize. Just for grins, I tried to init and it hung up but I was still able to eject it.