This should give you a quick insight of where the boot check code is on each bios. WPSET 400000,10000,RW (tells the debugger to break execution once a read or write to the cartridge connector region is attempted) If you want to catch this behavior using the MESS debugger do this at the debugger command prompt:įocus 0 (it will focus on the Mega Drive CPU, it usually defaults to the CD CPU) The (few) Japanese CD BIOSes I goofed around with don't try to detect a bootable cartridge. Īnd it boots before the CD BIOS shows it's splash screen. And here I thought we'd figured everything out on the CD.Īctually ElBarto and a few other people were talking about it in this very forum a while ago. Now onto researching how many variations of this boot system exist.Ĭhilly Willy wrote:Is this before or after the rest of the CD BIOS has been initialized? It's very interesting. Then I go to a different BIOS from same region (USA) and it's security data matches the security data from disc. Security data required for this boot up (SEGA-CD2, BIOS MPR-15511) is different from the data used for the disc but it can be easily extracted from the BIOS. The SEGA-CD LOGO/Planet screen is never shown. System boots from cold boot to SEGA CD boot LOGO then keep repeating the logo over and over.
Lame, I know, but for the purpose of checking the boot method.