[TMB_XV6700]

What you describe sounds like normal behavior if you unhide but don't unlock the extended rom before making changes to it. I've done that by accident before - made all sorts of changes that appear to work at first but then don't survive a soft reset. The extended rom unlocker is included in the current kitchen - you need to run it after finishing your flashing/hard-reset process. (You only have to do this once, then it's easy to forget later.)