Emulation itself is a legal practice. It falls under fair use and reverse engineering laws in many jurisdictions. However, distributing copyrighted BIOS files is a direct violation of copyright law. By dumping your own BIOS, you are acting within the bounds of the law and respecting the intellectual property of Sony.
The (Basic Input/Output System) is the firmware that runs when a console starts. For a PS2 emulator to work, it must simulate this firmware. ptwoe bios file download android
If you are starting fresh, you may want to consider more modern, actively developed emulators. Emulation itself is a legal practice