Last upgrade I planned for my Dreamcast was battery replacement. Dreamcast has a rechargable battery soldered to the board. Once it went dead (and those were made in 1999) the console would ask for a date every single time it boots.
Disassembling Dreamcast is easy. The solder points are also clear and unambigous. But when I tried to boot it, GDEmu would blink (so there’s some current), but the orange light won’t turn on. Turns out, the ribbon cable can be pulled on both ends, and while pulling it from the board, I also half disconnected it from the motherboard.
I also installed OpenMenu, a game dashboard, since GDEmu itself is very bare-bones, and doesn’t even have a list of games.