I have bored on about this before, but excellent advice from retailer in Koln early in my DCC adventure was that in the event of a decoder going non-responsive, with no obvious sign of failed components (visual, smell) or a broken connection; then do not discard, but keep trying decoder resets at intervals until the reset 'takes'. Been doing this ever since, sometimes needs a month or more of weekly resets, but if they do 'come around' they are fine afterwards, yet to have a subsequent failure.

Back in the day when they were the smallest decoder with a good drive - that was both available and at a sensible price - I bought some Lenz Silver minis. This would be about 2006. One of these went in a (now sadly late) friend's teeny HO loco and gave up after a couple of years for no apparent reason, and refused to reset. But I kept it, and chancing on it late last year, tried a reset and BEHOLD! it restored to Address 03 and was programmable. It has now completed six months service hardwired into a Bach 03, so is 'good'. I reckon it at 12 years from originally going unresponsive to finally resetting, 2009 - 2021. Any advance on that?