u/AbrocomaHungry3834

So I bought Yugioh World Championship 2006 for GBA, I started playing it and it seems to work fine. It’s got an auto save feature (it even gives me the “Saving, do not turn power off” message) and so I made some progress in the game and switched it off. When I came back to it, there was no option to continue my saved game, only to start a new one. This made me suspect the internal battery was needing replacement. I opened up the cartridge and noticed the layout is quite different to my pokemon GBA games. The connection points of the battery are different and there’s a black blob on the centre of the board. Anyone with experience able to shine some light on this?