The legitimate way to acquire scph70012.bin is to extract it directly from a physical PS2 console that you legally own.

: You can find your specific BIOS version by booting your PS2 with no disc or memory card, selecting "System Configuration," and pressing the "O" button. How to Get Your BIOS File Legally If you own an SCPH-70012 console, you can extract the required file using these steps: Modify your PS2

The only legitimate and safe method to get a "full" and correct scph70012.bin is to dump it from a PS2 console you own. Here is the standard process using free homebrew software: