While some emulators ("cores" in RetroArch) can run games without a BIOS file using a technique called "high-level emulation" (HLE), this often leads to compatibility issues, graphical glitches, or the absence of console-specific boot screens. Using the correct BIOS file ensures that the emulator behaves exactly like the original hardware, providing a bug-free and authentic experience. If a BIOS file is missing, RetroArch will often warn you with a "no bios found" message at the top of the screen.
Your neogeo.zip is incompatible. Use the Neo Geo BIOS v1.0 (Universe BIOS) or the standard set from MAME 0.220 or earlier. bios files for retroarch ps vita link
Copy your downloaded BIOS files directly into the ux0:data/retroarch/system/ directory. While some emulators ("cores" in RetroArch) can run