Mine was fun. I was only removing some interior lights from a timeclock schedule then uploading that 1 change. 6 hours later............. haha

Had to put the processor in Boot mode (dip switch 1), connect directly with a serial cable, AND (!) disconnect the ethernet cable and also the 232 cable going to the C4 system...and had to create a new blank file (wouldn't work with the existing file) and THEN re-upload the processor OS, then reopen the old programming and reload that to the processor.

Literally every one of those things had to happen for it to work.