Files are often named with their model number (SCPH‑####) and sometimes with region suffixes (e.g., SCPH‑50004_US.BIN). The internal contents and size (typically 512 KiB or 512 KB derivative for older chips; later consoles had different arrangements) matter more than filename.
Early Japanese units; known for minor glitches and lower compatibility. SCPH-3000X, 5000X all ps2 bios files including the new scph90006 exclusive