Go to Settings > Bios (or Config > Plugin/BIOS Selector in older versions).
If you own a physical SCPH-70004 console, it is important to be aware of a notorious hardware vulnerability associated with this specific model. The early 70004 Slims (V12 motherboards) suffered from a design flaw where the controller chip could accidentally send too much voltage to the laser lens mechanism, causing the laser to burn out rapidly or even melt the plastic housing. scph 70004 bios
The Slim BIOS revisions, such as the one inside the SCPH-70004, are highly sought after for emulation. Because Sony consolidated many chips (including integrating the original PlayStation's CPU as an I/O processor), the BIOS code was highly optimized. Go to Settings > Bios (or Config >