It's pretty much the same question I posted 15 years ago, still no answer!
https://www.avrfreaks.net/forum/...
If I can find the original firmware it may just be enough to reprogram it, I think I messed around with the T13 code at some stage.
I'm trying to stop my grandchildren "manipulating" the dices when we play monopoly, they always win. I may have a chance with the electronic dice...not that I would put any special code in it or anything like that......