Sega CD - Bios Rom Chip

I'm working on modding my Mega CD 2 to play every region's game. I have put a 40pin socket where the Bios used to be, and plugged the original bios on it.

I pretend to change that 128kb rom with a 512kb eprom containing all regional versions of the Sega CD Bios, but I don't know which eprom should I use, as it must be compatible with the original chip.

I would thank if anyone could help me with some info.