I've been trying to add formats to my Spreadsheet port and have hit yet another case of bad hex values. A side by side debug session revealed one minor bug, but I haven't found the big one yet. The few lame tests I've created all pass. File sizes are identical. I just have bad hex values being generated somewhere.
Well, if I get nothing else out of this experience I've become better at using 'od'.:)
UPDATE: - Found it! Turns out a 'prepend' was changed to 'append' in one method and one default value changed. Missed that in the first diff somehow. Time to test.