If you own the console, you can dump the BIOS using:
The 70012 is not "better" than the 39001. It is different . However, for games released after 2005 (like God of War 2 ), the 70012 is often more accurate because it matches the firmware those developers tested on. ps2 bios scph70012bin full
Once you have your verified scph70012.bin file, here is how to configure it in the most popular PS2 emulator, PCSX2. If you own the console, you can dump