I ordered these black buttons for my GameBoy Advance and sadly some of the buttons don't fit. I've been trying to fit the L&R buttons for maybe 2,5 hours. Also tried to replace the small metal pins with extra ones that came with the buttons. After another night sof trying to see what wrong the shell finally closed, but the L&R buttons were stuck and didn't move. Also the fill points of the mold are visible on the buttons and protrude. That's also a reason why they might not fit.
After that I Popped in some new grey buttons and everything worked fine, been playing with the GameBoy for a few days now and it's really clear that the black L&R buttons were the problem