sega dev running games

I can package the files you have sended to me.

My R10 SDK can run this game I will try to make a Ready To Use pack

I'm making a "How to" video to show my good way.

My way is particular, in order to avoid "Warning MAIN: Failed to prepare emulation" message.

http://www.megaupload.com/?d=9XBC4H34

NOTE : My Katana HDD is FAT32 formatted.

 

hi i clicked on my video enjoy but said page not found

 

Corrected

 

hi thanks and now works thanks to you

 

The reason these games do not run on a dev box has absolutely nothing to do with hardware at all, it is because these games look on the flash for the console region strings (to know what video mode they must enforce themselves to) (for instance when they see 211Dreamcast they are going to be set to 50hz (and usually display some choice between 50 and 60hz because the DC region video setting is on PAL50) on the other end, if it is set to 010Dreamcast then it is going to go straight to 60hz because the video output is set to NTSC60

The problem with that is that unlike the retail consoles, the region and video modes are enforced on the bios itself (the code from 0x120 to 0x16C is the one that does the trick) because of that, the devkit flash does not have any region string (it is filled with 0xFF). Thanks to that, the games that look for the video mode settings in the flash to know what video output they must be set to, do not find any proper value and that is precisely what makes them crash.

If you have any doubts you can test it yourselves, just set the region string on the flash to 0xFF (it would be best if you patch the bios first so it wont perform the region checks, otherwise the disc will fail to boot(because the region string will be corrupted)) (to do this go to 0x51E and set the value to 08A0)

I hope this solves yet another mystery.

P.S. this also means that writting an actual region string to the flash (despite that the dev bios does not use it) will allow you to run all those unworking games on your dev box. (assuming the flash on the devkit is fully writeable)

 

So, if we can modify the katana flash (not bios) we can run shenmue and other games ?

How can we disable this feature on the 1ST_READ.BIN to avoid reading flash and force VGA or Video mode ?

 

Yes you just have to modify the flash however make sure you DO NOT set the 0x0001A000 bit to 30 (the first 0 of the 00XYZDreamcast ASCII string) or you are going to brick your dev box (the bios refuses to boot if this value is set) You can set the other values fine though (so you just have to write 0XYZDreamcast instead)

As for disabeling the feature in 1st_read.bin I have no idea since I never looked into it before.

 

if you get this working let me know or pm me please

 

I don't know how to rewrite flash memory on the dev box

 

Probably the same way as on retail, through software (I doubt you actually have to solder the R512 on +12v like on retail, beside if you did I am not sure it is worthed to start soldering on a dev box motherboard for such a purpose, but my guess is the entire flash content is probably writeable through software on those already. Too bad the region changer isn't open source :/

 

Couldn't you acutally use your modified bios and flash on NullDC then use the "backup flash" option of region changer to dump the entire flash onto a virtual VMU, then put that file on a real vmu and used the Region changer on a retail DC (with RC mod done) to replace the retail flash witht he DEV one and remove the RC mod, then replace the bios with a chip ?

Just an idea ...

FG

 

Or you could just patch the bios before replacing it, then no need to even touch the flash. I thought we were talking of dev boxes here though

 

Well, the devkit BIOS can be easily flashed using a software that come with it.

Any chance you release your hacked bios?

FG

 

Are you sure of this? It seems the only way to verify this would be to modify the RO area of the DCs flash. I suppose this could be done on an emulator, so have you tested it?

Better yet run it with debugger on devkit and monitor the flash to see when it's read/written to.

It just seems odd to me that the region check function of such games would not take into account the possibility of them being run on a devkit.

 

Yes I have tested it on an emulator and it confirms it, the games (sega games such as shenmue 1 & 2, crazy taxi etc etc) wont run (even on retail bioses) when the region information is missing from the flash, when it is there they run fine even with hkt-0120 bios.

 

Ok, cool. Btw, I didn't mean to attack your conclusions, just wondered if they were speculation of proven .

It's quite possible from your method though that the games check if it's a devkit (which SEGA perscribed to be done through a register, not by reading the bios) and regardless of the bios enabled, the emulator will tell the game it's a retail DC.

The official libs had a number of checks for hardware revision to enable workarounds when necessary, so this doesn't seem to far fetched.


anyways... assuming you're right and they don't do any sort of check for devkit-ness (other than looking at the bios).

Since we know what flashrom block holds region info, and the workings of the syscall that gets flashrom info, it should be relatively easy (but non-trivial) to have that syscall read from a pre-made block when called on the RO block. AFAIK it's not possible to write to the RO area even on a devkit (though I've not tested).

 

well it can be done on a retail with a simple soldering, the dev box is probably the same, it might even be writeable directly, since I do not own a katana, I could never try to write the setting myself.

 

Thanks alot for the avi! Explain a lot what to do :clap:

 

woohoo, i got halflife running on my katana, i'll check if loading times are better that on a standard dc...

 

hmmm...no visible improvement...