Ultimately, the SCPH-90001 BIOS isn't a "magic fix" for better graphics, but it is the most polished version of a legendary system's DNA. It is the best choice for stability and late-model accuracy, even if it makes some legacy softmods a bit more complicated to execute.
Most PS2 fans are familiar with FreeMcBoot (FMCB), the exploit that allows you to run software from a memory card. Sony patched the "Update" vulnerability in the BIOS of later SCPH-90001 units (specifically those with a date code of 8C or later). This means that while the BIOS is "newer" and "better" for retail security, it is actually "worse" for users who want an easy, plug-and-play softmod experience. Users with these units often have to turn to FunTuna or Open Tuna as alternatives. Emulation Performance: Is Newer Better? ps2 bios scph 90001 better new
If you are sourcing a BIOS for use with PCSX2, the SCPH-90001 is a top-tier choice. Because it was the final retail version, it contains the most up-to-date instructions for the hardware's OSD (On-Screen Display). In emulation, using a 90001 BIOS often results in: Faster boot times into the main menu. Ultimately, the SCPH-90001 BIOS isn't a "magic fix"