If you attempt to run an NTSC-J (Japan) or NTSC-U (USA) game on this PAL v12 BIOS, the console will boot, but the BIOS forces the vertical refresh to 50Hz. Many early PS2 games hard-coded for 60Hz would exhibit "screen crunching" or audio desync unless the COH-55000 region check was bypassed via patches.

Confirms the region lock and language defaults. An EUR BIOS expects a PAL 50Hz/60Hz signal, defaults to languages like English, French, German, Spanish, Italian, and crucially, uses a different DVD remote control frequency than NTSC units.

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