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To use UniBIOS v2.3 in an emulator, you typically need a file often named neogeo.zip containing the BIOS ROMs. Placement: Place your neogeo.zip (containing uni-bios_2_3.rom or similar) into your emulator's Configuration: In RetroArch, go to Quick Menu > Core Options > Neo-Geo Mode and set it to Use UNIBIOS Activation: uni bios23 zip
When you download uni_bios23.zip , you typically find: Go to Google and search exactly for: To use UniBIOS v2