The checks are on the games, not on the BIOS. Once the BIOS were hacked and games started to boot, I found out the games would fail EXACTLY the same way they used to when I were trying to boot them with DATEL CDX-PRO.
So I just suggest that people use JPN bios on their region free systems. I patched a LOT of different BIOS ROMs for several different regions/versions of MEGA-CD consoles.
Yes you are the guy who made hacks on sega-16 thread also. Is there possibility to change dash to eu style and US style for JP bios?
So we would need to studi whats different code in the jp than eu and us. there has to be some instructions that handles differently in JP than EU and US. Even sega had a multiregion bios for developers so it must of been JP like bios with region checking disabled.
How ever, Only possible solution for Multimega bios mod is region free bios. As there is no direct swap SOP40 eeprom chip out there that could be used as multibios chip. Only possible solution is to use patched 1mbit sop40 eeprom that is very common chip and include with it regionfree bios.
It's very interesting matter, I saw in some post on interenet, that changing bios region code to JUE would make bios region free. Is this true? They opened the bios with ascii editor if I remember right and edit the password thrue that.
How ever europeans would love EU look bios and US people would enjoy US bios. This is why in my opinion it is worth while to study the matter and become true sega 16bit genious hero!
And if jp bios is only possible so does lates cd2 model jp bios support running in multimega? Atleast one german firm makes mutltibios modding to cdx/multimega and I guess they are using cd2 bios for jp.