Dreamcast Devbox Bios on retail Console!

Read through the thread? MX chip for different bios, DC region changer for orange colour

 

Just got around to doing this yesterday, I love it. Brilliant work Link83, and a big thank you to DarthCloud for making the original DC-Swat instructions a bit easier to follow and adding a lot of extra info.

I also made a selfbooting nero image of the DreamShell disc, which has been altered to make it even easier to flash Link83s BIOS:



Grab the Nero image from http://www.mmmonkey.co.uk/console/download.htm, please feel free to mirror it

Pete

 

I've never had a problem with NRG vs CDI image types, just data/data vs audio/data. Whatever Dreamshell uses originally works fine across every DC I've tried it with. The CDI file floating around in this thread I've never gotten to boot on anything but a DC I have made late 99. Every 2000 model accepts it as a bootable disc, reads IP.bin without the Dreamshell logo and drops to a black screen.

Will have to give this NRG version a shot.

 

I made a note of DarthClouds post that says how to get his CDI booting

http://assemblergames.com/forums/showpost.php?p=446263&postcount=143

(Using a boot disc to boot it, pressing Y before A when selecting the .bin file to launch dreamshell)

When I used BootDreams to make the disc image, my CDI actually failed, but the NRG file worked fine so I just stuck with that

Pete

 

My disc should be only used with older dreamcast from 1999 with heatpipe and need to use DreamLoader boot disc to work.

 

aha, thanks for the info.

 

Here is a perfect image working for the 1999 model with heatpipe including link83 bios.
I repacked it in audio/data track + small dummy. It works on my jap dc with heatpipe from 1999. I bet, it will work for all those model from 1999.
No need from a boot disc, etc...

Stand alone disc with link83 bios :

http://www.megaupload.com/?d=M33J16K3

The sd loader disc :

http://www.megaupload.com/?d=EFE7J8NK

Hope it will be useful...

 

would it be possible to also modify the dreamcast bios to support a bigger memory card rather then this 200kb crap?

 

I read back the thread and I guess I need to make thing a bit more clear about getting the mod to work on VA0 motherboard (Heatpipe model with 5V BIOS ROM).

Some suggested to use 29F160 chip instead of 29LV160 since those are rated for +5v. At first you could think this make sense but not really. This is a TSOP-48 only chip anyway, should work yes but will require more work.

All dreamcast either VA0, VA1 or VA2 use the very same CPU/GPU and bus are +3.3v. (I confirmed this on my VA0 with my scope with 3.5v max on the address bus).

How the +5v BIOS chip used in VA0 can handle high bit if the max is 3.3v? Chip don't expect to get exactly 0v or 5v. Their is a range for '0' and one for '1'. For 5v chip it's something like -0.2v to 0.8v for '0' and 2v to 5.5v for '1'. Since the minimum is 2v the 3.3v on the bus is enough for the chip to recognize the '1'.

So you can use 29LV160 chip on your VA0 dreamcast, just make sure to obviously power it with +3.3v and NOT with +5v. The bus is +3.3v so their is no problem at all if you give it the right power input.

Btw hellbelly great tutorial. If I can make some suggestion, I would put as first step to identify the dreamcast motherboard then link within the page to the VA1/2 instruction or the VA0 one. At the beginning of either section, I would make a title in bigger character to clearly identify the section as the instruction of VA1 or VA0.

megaupload don't work right now but I going to try with mine. I guest we should all use this one if it work on all dreamcast.

 

Tried your disc with my DC lolof and it work perfect! Good work. If it work with VA1 system too, I guess we should all use this one instead!

 

It will work only on the DC who can boot audio/data cession, not on the non mil-cd compatible one.

 

I've done some better looking schematic for both VA0 & VA1 the original one is too small.

 

Cheers DarthCloud, when I'm awake properly I'll re-arrange it properly, for now i've moved Link83s info about boards to the top of the page, and linked to your post with the fantastic new diagrams in

Pete

 

Bon travail Jacques!

[EDIT]
Malgré ton erreur de copier/coller!

C'est bon de voir des Québécois desfois!

 

I made a copy/paste error in the VA1 circuit but it's now corrected, and reuploaded. So hit refresh to make sure you are viewing the right one

 

Much nicer schematic there. Thanks!

I'm not so sure the BIOS was the limitation honestly. I would imagine that if it was the VMU's fault someone would have made a 3rd party memory card that had more space available. I have the Nexus 4x memory card but it uses a paged system where you can clearly see the 4 SST chips inside for each of the pages.

If it is a BIOS limitation it might be hackable to increase the limit but you'd have to build a correspondingly large memory card. You'd also have to cross your fingers and hope there aren't some limitations built into games across the board or at random.

 

There are bigger Dreamcast memory cards available, third party. They don't have the screen or any of that associated functionality, but I think the biggest go up to 16X standard VMU size. I'm pretty sure they don't even need bank switching (like some third-party PSX cards do).

 

Thanks for the schematics DarthCloud, made things a whole lot easier.
I've fitted a 29LV160 into my VA0, works perfectly.

Some pics, click to enlarge:

 

umm i remeber l_oliveira makeing a post in the dreamcast blueprint thread
that the original bios chip contained an extra 128kb of flash

here is the post

would it be possible to use this to flash the modified bios?
might be alot simpler then soldering a piggybacked bios chip

 

The "flashrom" chip he references is not the BIOS chip. All BIOS chips are 2mb in size. The flashrom referenced is normally 128kb but some are 256kb.

The flashrom being that which stores region data and the PSO ver2 serial number amongst other items. As such you can't modify existing Dreamcasts to flash a new BIOS onto as the BIOS chip is mask rom and not writable.

Even if you could write a BIOS to the flashrom and have it bootable the BIOSes available are all 2mb, not 128kb or 256kb.