Dreamcast modchip, R422 mod, Laser repair, and other questions

[Link83]

Hi everyone, Im new here so please forgive me if I have posted this in the wrong section. I have posted this elsewhere but am hoping that I get more reponses here as this site seems to be a fountain of knowledge! 

I am hoping to mod my Dreamcast to be universal - Playing any region game and displaying it all at 60hz, but I need some help/advice first.

I have put my main questions in bold as this post ended up being alot longer than I had initially planned!

1) I just wondered who still sells the latest/last revision of the 4 wire Dreamcast Modchip?

I have been told that this site still sells them:-
http://www.robwebb.clara.co.uk/shop/dc/dc.htm
But I dont know if that is the latest/last revision of the modchip. Is there anyway to know? Or is there any other sites people know of?

2) Is there any actual hardware differences between a NTSC and PAL console apart from the PSU?

I only ask as now that there is a 'region changer' disk which flashes the Dreamcasts flash memory:-
http://www.lyris-lite.net/fu_archives/000601.html
Surely a PAL Dreamcast console flashed to NTSC would be exactly the same as an NTSC console in every respect? Unless the actual Bios or Motherboard is different aswell? (I know the Bios was definitely different on later NTSC models to disable the use of CD-R's in the Mil CD format)

'Back in the day' I remember it being said that its always best to modchip an NTSC Dreamcast console, as modchipped PAL consoles had trouble displaying NTSC games at 60hz, but I guess if they are exactly the same hardware wise, and just had a different flash, this point would now be redundant?

3) Does anyone know what exactly the 'R422' mod does/changes? :-
http://www.mmmonkey.co.uk/console/sega/dc-ntsc-pal.htm
I have read allsorts of conflicting information from "it converts NTSC to PAL" to "it just changes NTSC to PAL60" and "it switches between 50hz and 60hz"

My 'guess' is that it just changes the output of an NTSC machine to PAL, but does NOT alter the refresh rate of the console - so it would still play in 60hz (unless the game is PAL 50hz only) This makes it more compatable with some PAL games, however I could be totally wrong....

4) Can you still solder the R512 points and use a region changer disk with a modchipped Dreamcast console?

5) What is the recommended range in ohms for the Dreamcast Lasers Potentiometer (POT)?

I have read allsorts of guides for adjusting Gamecube and Xbox lasers correctly, but none for Dreamcast  - they all seems to suggest you just keep turning the POT in 1/8th turns until it works, which isnt very accurate/scientific to say the least!

6) Has anyone tested what (if anything) the other 'R' points do/change? (eg R423, R425 etc)
Picture from mmmonkeys site:-

I read here (4th post):-
http://dcemulation.com/phpBB/viewtopic.php?t=1776
That bridging R424 forces an NTSC output - but that may be wrong, as I have not read it anywhere else.

Sorry for such a long post and thanks in advance for any help or advice you can give me

[ken_cinder]

1: I do believe the "revision" has nothing to do with the internals, just a nicer little PCB etc. Early and basic chips were nothing more than the IC itself. There isn't much to this thing.

2: The only insight I can offer here, as I've never touched a PAL Dreamcast, is that the Bios is IDENTICAL between all region Dreamcast.
Regional differences are contained within the flashrom. The bios is hardcoded and NOT reprogramable. I believe the modchip serves the purpose replacing the flashrom no?
The bios and flashrom are different chips (Modchip installation diagrams point you to the flashrom, NOT the bios. Theres all sorts of settings and crap stored in there, even games store their ID and region details in there, go figure).
If you can flash the flashrom with suitable data, such as a devkit flashrom, you wouldn't need a chip. kOS can do this. Can't help further, sorry.

3: No can answer.

4: No can answer, but why would you want to if you chip/flash flashrom to serve this purpose?

5: This is honestly subjective, I've repaired dozens of Dreamcasts and just like the Gamecube, the ohm value varies considerably, especially between different laser versions (More than 2? I dunno) and all worked well at differing values, even new assemblies. Factory adjusted to optimal pickup I assume, rather than any 1 value.

6: No idea, never bothered with that, however if it's anything like the Saturn. You can wire up a nice little dip switch board and change regions as well as refresh rates with certain combinations. That is, if those pertain to those things (I'd assume based on your comment, and the fact only certain points are bridged.....they do)

Wish I could be more helpful. Said what I could. Sorry

[Link83]

Thanks very much for your reply and advice 

1: I do believe the "revision" has nothing to do with the internals, just a nicer little PCB etc. Early and basic chips were nothing more than the IC itself. There isn't much to this thing
So there is no different programming code on the IC chips themselves?

2: The only insight I can offer here, as I've never touched a PAL Dreamcast, is that the Bios is IDENTICAL between all region Dreamcast.
Really? Is there no difference between the BIOS on a Mil-CD and non Mil-CD compatable Dreamcast?
Regional differences are contained within the flashrom. The bios is hardcoded and NOT reprogramable. I believe the modchip serves the purpose replacing the flashrom no?
I think that the modchip simply tells the system to bypass the region check on inserting a disk - it doesnt actually change/alter or replace the flashrom in any way.
The bios and flashrom are different chips (Modchip installation diagrams point you to the flashrom, NOT the bios. Theres all sorts of settings and crap stored in there, even games store their ID and region details in there, go figure).
If you can flash the flashrom with suitable data, such as a devkit flashrom, you wouldn't need a chip. kOS can do this. Can't help further, sorry.
I think this has been attempted but no-one has managed it yet, as the development box used dipswitches to choose the region, and they cant use the exact flash off a dev box as apparently it wont work with a retail Dreamcasts bios Theres some more info in this thread:-
http://dcemulation.com/phpBB/viewtopic.php?f=31&t=89863&st=0&sk=t&sd=a&start=40

3: No can answer.
OK thanks

4: No can answer, but why would you want to if you chip/flash flashrom to serve this purpose?
Well, only the flashrom dictates the refresh rate of the system, (which the modchip does not alter) so it would be useful to change the system between 50hz and 60hz whenever I wanted.

5: This is honestly subjective, I've repaired dozens of Dreamcasts and just like the Gamecube, the ohm value varies considerably, especially between different laser versions (More than 2? I dunno) and all worked well at differing values, even new assemblies. Factory adjusted to optimal pickup I assume, rather than any 1 value.
Do you have an approximate range to go off? - Im trying to fix a Samsung GD Drive that a friend tried to fix himself but has turned the POT one too many times and doesnt know where it was to start with 

6: No idea, never bothered with that, however if it's anything like the Saturn. You can wire up a nice little dip switch board and change regions as well as refresh rates with certain combinations. That is, if those pertain to those things (I'd assume based on your comment, and the fact only certain points are bridged.....they do)
Yeah, I think that may be the only way I am going to find out...

Wish I could be more helpful. Said what I could. Sorry

No need to be sorry, you have been a great help - all advice is very much appreciated 

[ken_cinder]

1: I can't imagine any change. The chip does 1 simple thing, bypass regional protection. You're certainly better off with that v3, if only for the nice little PCB.

2a: NOTHING, NADA. Even devkits are the same, the only difference is the flashrom (In which the Devkit has dip switches setup for using different flashroms). The BIOS is really nothing more than just that, Basic Input/Output System. All the "work" is done by whats in the flashrom.
2b: I know it doesn't "replace" it, but it serves in replacing what the flashrom reports back for regional settings. Poor choice of words.......

4: Never thought of that, but you're probably better off using the points located in your #6 to achieve this with a switch. Much less hassle no?

5: It's late right now and I'm fairly busy this week, but I'll try to get back to you on Thursday or Friday with a reading from my primary unit. I've tweaked the pot so the drive reads even CD-RW, so it's gotta be a good value to start at when you're lost.

[Link83]

1: I can't imagine any change. The chip does 1 simple thing, bypass regional protection. You're certainly better off with that v3, if only for the nice little PCB.
OK thanks 

2a: NOTHING, NADA. Even devkits are the same, the only difference is the flashrom (In which the Devkit has dip switches setup for using different flashroms). The BIOS is really nothing more than just that, Basic Input/Output System. All the "work" is done by whats in the flashrom.
Do you know why later Dreamcasts units were not able to read the Mil-CD format then? Was there an alteration made in the hardware or the flashrom that prevented the Mil-CD format from loading?
2b: I know it doesn't "replace" it, but it serves in replacing what the flashrom reports back for regional settings. Poor choice of words.......

4: Never thought of that, but you're probably better off using the points located in your #6 to achieve this with a switch. Much less hassle no?
Well, I would love to use the 'R' points to make a physical 50/60hz switch if it was possible - but no-one has managed to do it so far 

5: It's late right now and I'm fairly busy this week, but I'll try to get back to you on Thursday or Friday with a reading from my primary unit. I've tweaked the pot so the drive reads even CD-RW, so it's gotta be a good value to start at when you're lost.
That would be fantastic  Also, could you tell me which points I should be putting the multimeter on and what I should have it set to? Heres some pics:-


Thanks again

[ken_cinder]

Mil-Data format would have been blocked by the flashrom. The bios itself doesn't do any regional coding detection or disc verification.

I also don't think the Mil-Data thing or Dreamcasts made after a certain date being unable to read backups is true, I KNOW the backups thing was disproven long ago and you can find the list they WERE compiling which is now shown that ALL units can read backups on DCEmu.co.uk somewhere. If Mil-Data is an issue with some units still, that would probably be a firmware issue on the GD-ROM itself, and nothing to do with the Dreamcast. There is so much speculation and myth surrounding the Dreamcast it's not funny, I'm STILL shooting down rumours that "Dreamcasts made after 199X can't read backups".

As for the points, you'd put your multimeter on either side of the potentiometer and set your multimeter to 2000 ohm point (Your resistance may very well be over 200) and simply take the output from the screen.

[l_oliveira]

Few info I'd like to add to the thread:

1- The bios does all regional and security checking. It reads a flag in the flash at the first boot after power on to know which region it has to behave as.

2- It also stores the video system, initial language settings (for 1st power on after un-boxed) and a unique per unit ID number. (Edit: Here I mean the flash)

3- Early japanese consoles (with heatpipes) use a older bios which don't support region flag in the flash. Putting that bios on a newer dreamcast would cause it to behave as a japanese unit regardless what setting it has on the flash. Also it is worth mention that the old bios is made for boards with 128KB of flashrom and might not work properly on newer motherboards...

4- Lattest units can still run MIL-CD but older pirated game discs won't boot because the bios now refuses to boot discs which the first track is of the "AUDIO CD" data type. I assume that no real MILCD has the first track as audio.  Pirates eventually found that out and could again make bootable dreamcast discs. Others resourced to scavenge bios roms from broken Dreamcast units to "mod" theirs.


On my region hack I used an 3V 2MB TSOP  flash rom with an adapter to "burn" an hacked bios (multi region) on my dreamcast. I did peel out the original maskrom chip and soldered the programmed TSOP to it.

MPR-21068  Early japanese bios on heatpipes cooled units
MPR-21931  Early USA units with heatpipes and onward...
MPR-23588  I found this bios ROM on a US unit with single board (GD-Rom and CPU are 1 board) MIL-CD boot code patched.


Pictures of the hack are attached.

By the way, on the old boards of "VA0" revision (Board with heatpipes) the flashrom size is 128KB. Newer Dreamcast units have 256KB flashroms.
The dreamcast shown is a USA VA0 board which had an MPR21931 bios.

[NeWmAn]

On my region hack I used an 3V 2MB TSOP  flash rom with an adapter to "burn" an hacked bios (multi region) on my dreamcast. I did peel out the original maskrom chip and soldered the programmed TSOP to it.

Is the hacked bios (or the info needed to create it) downloadable somewhere?

[l_oliveira]

Not that I know of.  PM me if you're interested.

[l_oliveira]

Better yet, take the vanilla DC bios (Dump from MPR21931 that is used with emulators  md5-128: E10C53C2F8B90BAB96EAD2D368858623)
and hexedit this :

00000510   72 C4 07 C9 03 66 05 E1  1D 40 0C 34 0C 35 1E B0   r�.�.f.�.@.4.5.�

into this :

00000510   72 C4 07 C9 03 66 05 E1  1D 40 0C 34 0C 35 08 A0   r�.�.f.�.@.4.5.

Basically change 1E B0 at 51E/51F to 08 A0.

And you hacked the bios.

Put it back into a flash chip, solder it to the dreamcast and happy playing

[NeWmAn]

Thanks! 

[Link83]

Few info I'd like to add to the thread:
Thanks you 

1- The bios does all regional and security checking. It reads a flag in the flash at the first boot after power on to know which region it has to behave as.
Thanks that explains alot.

2- It also stores the video system, initial language settings (for 1st power on after un-boxed) and a unique per unit ID number. (Edit: Here I mean the flash)
Ah, I understand. Any idea what the 'per unit ID number' is? Is it the same as the consoles serial number?

3- Early japanese consoles (with heatpipes) use a older bios which don't support region flag in the flash. Putting that bios on a newer dreamcast would cause it to behave as a japanese unit regardless what setting it has on the flash. Also it is worth mention that the old bios is made for boards with 128KB of flashrom and might not work properly on newer motherboards...
Do you have any idea how many motherboard revisions there have been for the Dreamcast? I am guessing there was 3 versions (VA0, VA1, and VA2.1) but im not sure...

4- Lattest units can still run MIL-CD but older pirated game discs won't boot because the bios now refuses to boot discs which the first track is of the "AUDIO CD" data type. I assume that no real MILCD has the first track as audio.  Pirates eventually found that out and could again make bootable dreamcast discs. Others resourced to scavenge bios roms from broken Dreamcast units to "mod" theirs.
Makes alot of sense, thanks.


On my region hack I used an 3V 2MB TSOP  flash rom with an adapter to "burn" an hacked bios (multi region) on my dreamcast. I did peel out the original maskrom chip and soldered the programmed TSOP to it.

Have you written a guide about it at all? I would love to know exactly how you did it/what you used. Also, have you tried putting a HKT-0120 Bios on a retail Dreamcast? I would love to know if that would work!

MPR-21068  Early japanese bios on heatpipes cooled units
MPR-21931  Early USA units with heatpipes and onward...
MPR-23588  I found this bios ROM on a US unit with single board (GD-Rom and CPU are 1 board) MIL-CD boot code patched.

Does the bios used correspond exactly to the motherboard revisions? eg:-
VA0  = MPR-21068
VA1  = MPR-21931
VA2.1= MPR-23588
Or do they not match up like that?

Also, I did a google search and came across a thread which said there is an MPR-21931-X1 and an MPR21931-X2 bios - do you know if there is any difference?


Pictures of the hack are attached.

By the way, on the old boards of "VA0" revision (Board with heatpipes) the flashrom size is 128KB. Newer Dreamcast units have 256KB flashroms.
The dreamcast shown is a USA VA0 board which had an MPR21931 bios.

Do you have any idea what bios/flashroms and motherboards were used on PAL Dreamcasts? Im guessing PAL units only used VA1 motherboards as I have not yet come across any units with heatpipe cooling, or any with the GDRom assembly built into the motherboard (like later Japan and American consoles) but I would love for it to be confirmed

[l_oliveira]

Ah, I understand. Any idea what the 'per unit ID number' is? Is it the same as the consoles serial number?

Yes, that was used on a few games, like for example the first version of Phantasy Star Online (the japanese 1.0 version only) for savegame
encryption, as a attempt to bind the character files to the Dreamcast unit used to play the game. Later on they decided to use the S/N of
the game disc (as on the gamepackage) as encryption key. The unique ID is a 64 bit number. So is the PSO serial number in the box (lol)


Do you have any idea how many motherboard revisions there have been for the Dreamcast? I am guessing there was 3 versions (VA0, VA1, and VA2.1) but im not sure...

the 2nd version of bios was out when the NA unit released. It was used on all Dreamcast units until late 2000 when they tried to patch the MILCD boot, when the third version of the bios was introduced.

Have you written a guide about it at all? I would love to know exactly how you did it/what you used. Also, have you tried putting a HKT-0120 Bios on a retail Dreamcast? I would love to know if that would work!

No guide was written about this. Also, I'm not the author of the binary patch. It's based on the hacking made by one of the modchips.
Also I liked the idea of trying a dev unit bios on the retail unit. Even though I think it might lack a lot of hardware that is present on the dev unit.


Does the bios used correspond exactly to the motherboard revisions? eg:-
VA0  = MPR-21068
VA1  = MPR-21931
VA2.1= MPR-23588
Or do they not match up like that?
Also, I did a google search and came across a thread which said there is an MPR-21931-X1 and an MPR21931-X2 bios - do you know if there is any difference?

A good example is the Tec Toy Dreamcast. It's first batch are old VA0 japanese dreamcasts which were converted and re-flashed.
They had the bios changed from V1.0 to V1.1 and had the videosystem changed to PAL60. The DC hackers ignorant about the brazilian video system assumed we used 50Hz here. It's funny because that makes the pirated DC games unplayable on brazilian dreamcasts as it gets black and white 50hz video output on brazilian TVs (It does output PAL-B/G/I like if it were a european Dreamcast)

Then after the Dreamcast died, Tectoy imported a ton of european (blue swirl) units and sold here, too. They reflashed them for PAL60/ PAL-M video standard.

As far I know the X1 and X2 are just datecodes. We should try dumping them.

Do you have any idea what bios/flashroms and motherboards were used on PAL Dreamcasts? Im guessing PAL units only used VA1 motherboards as I have not yet come across any units with heatpipe cooling, or any with the GDRom assembly built into the motherboard (like later Japan and American consoles) but I would love for it to be confirmed

I think PAL units used only VA1 boards. When DC released in Europe the stock of VA0 units was gone already. USA VA0 units are rare here, but they do exist.  I don't know how it is in the USA.

Other interesting thing I'd like to share is that one time I opened a Korean Dreamcast and found a different GD-Rom drive board.
It had 1MB of cache !!!!  I'll look here if I still have that drive board here and take a picture of it.

[Link83]

To confirm the answers to most of my original questions I thought I would put the answers (as I understand them so far) underneath my original questions, and if anyone notices a mistake please point it out to me!

Is there any actual hardware differences between a NTSC and PAL console apart from the PSU?
No, there is no difference in the actual Dreamcast motherboards (When comparing between an NTSC VA1 board and a PAL VA1 board) So flashing a PAL console to NTSC will make it EXACTLY the same as an NTSC console (except for the orange swirl sticker!) - It even means that a PAL console flashed to NTSC would need the "R422 fix" mod that is usually only used on NTSC consoles

3) Does anyone know what exactly the 'R422' mod does/changes? :-
http://www.mmmonkey.co.uk/console/sega/dc-ntsc-pal.htm
I 'think' I understand this now...
I read about bridging R424 forcing a PAL machine into NTSC, here:-
http://dcemulation.com/phpBB/viewtopic.php?t=1776
So heres my guess as to how it works:-

No Dreamcasts from any region have R422/R424 bridged from the factory.

On any Dreamcast console flashed to NTSC
Bridging R422 forces the video signal output to PAL. (Of course this mod has no affect on a standard PAL machine as it already outputs PAL)

The console is still set to 60Hz only, so the output is PAL60hz (Unless its a PAL 50hz only game such as PAL Skies of Arcadia)

This also has the added benefit of 'fixing' the few PAL games which only played in 50hz into having a stable picture on an NTSC Dreamcast, as these would otherwise often be displayed in black and white and/or have a rolling picture.

This is because PAL 50hz is a conventional video standard and supported by many TVs. If this mod Is not done the console would be outputting an NTSC 50Hz signal with these games - which is not a conventional video signal (As there is no such thing) and this would makes many TVs go mental! (Scrolling and playing in black and white)

On any Dreamcast console flashed to PAL
Bridging R424 forces the output to NTSC. (Of course this mod has no affect on a standard NTSC machine as it already outputs NTSC) The console will output 50hz by default as it is PAL, so is also a weird combination of NTSC 50hz (Unless 60hz can be selected in the game) This of course means no-one would ever really want to perform this mod as it has no practical use whatsoever!

PLEASE NOTE!
Neither mod has any effect on the consoles default refresh rate or 50 or 60hz, which is set by the consoles video region in the flash (NTSC-60hz, PAL-50hz)

Also, note that the changing of the video output to PAL or NTSC would only be noticeable when using the RF, Composite, or S-Video connections.

Scart and VGA are both RGB and so are neither NTSC or PAL

4) Can you still solder the R512 points and use a region changer disk with a modchipped Dreamcast console?
Still dont know, but my guess is "yes"?
Although I should say now that you should definitely fit a switch if you perform this mod, as it has been reported by many users that some games try to write to the flash when playing, and if you dont fit a switch (To choose when to use the region changer disk or not) you run the risk of the game accidentally writing over the systems flash and breaking your Dreamcast

5) What is the recommended range in ohms for the Dreamcast Lasers Potentiometer (POT)?
Would still like to know this - im trying to fix the Samsung GD-Rom drive but every adjustment I have made doesnt seem to work. The disk spins up at first and then slowly slows down as the Dreamcast goes to the main menu. I can alter the range anywhere between 570 and 3260 ohms, but still havent managed to get it to work 

6) Has anyone tested what (if anything) the other 'R' points do/change when linked/jumpered? (eg R423, R425 etc)
Still would like to know this too! If no-one has tried I think I might try to do it myself on a spare motherboard...

------------------------------------------------------------------------------------------------------------------------------

Also, thanks for all your replies l_oliveria, I have tried to answer/reply to most of your points:-

the 2nd version of bios was out when the NA unit released. It was used on all Dreamcast units until late 2000 when they tried to patch the MILCD boot, when the third version of the bios was introduced.
Ah, so they dont match up with the motherboard revisions then. Do you know if the 3rd bios revision was only used on the VA2.1 motherboards? Or are there VA1 motherboards with the 3rd bios revision aswell?

No guide was written about this. Also, I'm not the author of the binary patch. It's based on the hacking made by one of the modchips.
It would be great if you could/did write a guide one day - I would love to try it myself but without a guide I think I would be abit lost! I have no idea how to do it or what hardware I would need, although I am very impressed by your mod

Also I liked the idea of trying a dev unit bios on the retail unit. Even though I think it might lack a lot of hardware that is present on the dev unit.
Apparently the dev units flash chip is empty (or unused) - so all region settings on the Dev unit are made by the bios, using dip switches. The Dev unit bios sounds quite alot like the first Japanese Dreamcasts Bios you mentioned before (the VA0 with 128kb of flash) I wonder if it would work on one of those models, if not on the VA1?
...Even though I guess it would be abit useless as the Dev unit doesnt support CDR or region free settings it would still be very cool to see the Dev Units start up animation on a retail Dreamcast 

A good example is the Tec Toy Dreamcast. It's first batch are old VA0 japanese dreamcasts which were converted and re-flashed.
They had the bios changed from V1.0 to V1.1 and had the videosystem changed to PAL60.
Thats interesting - how were Tec Toy able to re-flash the 128kb Flashram on the Japanese VA0 when the flash was not originally used by the V1.0 bios? Would be interesting to get a dump of the 128kb flash on those units to see how it compares to the flash on the common 256kb models....

Also, were the different bios actually called V1.0, V1.1 and V1.2 by Sega in the actual Bios code, or is that just what they are usually called by modders?

The DC hackers ignorant about the brazilian video system assumed we used 50Hz here. It's funny because that makes the pirated DC games unplayable on brazilian dreamcasts as it gets black and white 50hz video output on brazilian TVs (It does output PAL-B/G/I like if it were a european Dreamcast)
Does the R422 (or even the R424) mod fix this at all?

Then after the Dreamcast died, Tectoy imported a ton of european (blue swirl) units and sold here, too. They reflashed them for PAL60/ PAL-M video standard.
I did not know that!

As far I know the X1 and X2 are just datecodes. We should try dumping them.
Would love to dump it if I knew how to!

I think PAL units used only VA1 boards. When DC released in Europe the stock of VA0 units was gone already. USA VA0 units are rare here, but they do exist.  I don't know how it is in the USA.
Thats what I thought too Also, Sega Europe seemed to have greatly overstocked on Dreamcast consoles and accessories, so I dont think they ever needed to produce PAL Dreamcasts with the VA2.1 motherboard - Which would mean all PAL units are VA1 and probably only ever used the V1.1 bios. Would be very interested to hear otherwise though!

Other interesting thing I'd like to share is that one time I opened a Korean Dreamcast and found a different GD-Rom drive board.
It had 1MB of cache !!!!  I'll look here if I still have that drive board here and take a picture of it.
That would be great to see! the only interesting drive I have seen is the one used in the NTSC VA2.1 motherboard, like this:-

By the way, was there ever a VA2 Dreamcast motherboard released/used? Or only VA2.1?

Thanks again for everyones contributions so far

[l_oliveira]

------------------------------------------------------------------------------------------------------------------------------

Also, thanks for all your replies l_oliveria, I have tried to answer/reply to most of your points:-

Ah, so they dont match up with the motherboard revisions then. Do you know if the 3rd bios revision was only used on the VA2.1 motherboards? Or are there VA1 motherboards with the 3rd bios revision aswell?

The 1.1 bios support VA0 and VA1 boards perfectly. So it should work fine with either 128 or 256 kb flash.

Apparently the dev units flash chip is empty (or unused) - so all region settings on the Dev unit are made by the bios, using dip switches. The Dev unit bios sounds quite alot like the first Japanese Dreamcasts Bios you mentioned before (the VA0 with 128kb of flash) I wonder if it would work on one of those models, if not on the VA1?
...Even though I guess it would be abit useless as the Dev unit doesnt support CDR or region free settings it would still be very cool to see the Dev Units start up animation on a retail Dreamcast 

I don't know but I remember years ago a hacker group mention that the dreamcast can boot rom connected to it's G2 BUS. They also mentioned that the earliest units had debug/test code on it's rom. Few pics of their hardware were floating on the net ...

Thats interesting - how were Tec Toy able to re-flash the 128kb Flashram on the Japanese VA0 when the flash was not originally used by the V1.0 bios? Would be interesting to get a dump of the 128kb flash on those units to see how it compares to the flash on the common 256kb models....

They were SEGA's partner back then so they had tools and software from SEGA for doing it.

Also, were the different bios actually called V1.0, V1.1 and V1.2 by Sega in the actual Bios code, or is that just what they are usually called by modders? I am calling them that way just to point out that they are different.

Does the R422 (or even the R424) mod fix this at all?
no, the hacked games also do the disservice of switching the PVR to 50hz mode

I did not know that!


Thats what I thought too Also, Sega Europe seemed to have greatly overstocked on Dreamcast consoles and accessories, so I dont think they ever needed to produce PAL Dreamcasts with the VA2.1 motherboard - Which would mean all PAL units are VA1 and probably only ever used the V1.1 bios. Would be very interested to hear otherwise though!

The PAL units sold here only needed to be reflashed. I think they don't even need to open the units to flash... We just don't know yet what software register we have to poke to unlock the protected region in the flash. The jumper do that for us and allow homebrewn tools to flash the protected sectors.

That would be great to see! the only interesting drive I have seen is the one used in the NTSC VA2.1 motherboard, like this:-

By the way, was there ever a VA2 Dreamcast motherboard released/used? Or only VA2.1?

It's VA2.1, just like the one in the picture ...

Thanks again for everyones contributions so far

This is looking good

[Chizzles]

This is slightly off topic, but has anyone noticed that with a boot-disc on an umodded PAL Dreamcast, some NTSC games run at optimized (albeit poorly) 50Hz?

Space Channel 5 Part 2 runs at 50Hz, it's frameskipped, but the timing and speed are correct.

[KillingBeans]

3) Does anyone know what exactly the 'R422' mod does/changes? :-
http://www.mmmonkey.co.uk/console/sega/dc-ntsc-pal.htm
I have read allsorts of conflicting information from "it converts NTSC to PAL" to "it just changes NTSC to PAL60" and "it switches between 50hz and 60hz"

My 'guess' is that it just changes the output of an NTSC machine to PAL, but does NOT alter the refresh rate of the console - so it would still play in 60hz (unless the game is PAL 50hz only) This makes it more compatable with some PAL games, however I could be totally wrong....

I've got my own theory on the R422 subject:

http://dcemulation.org/phpBB/viewtopic.php?f=31&t=97072

I think it makes the machine forget about its own PAL/NTSC setting and "follow" the game instead.

JAP/US games give NTSC output, and EU games give PAL output... just a theory 

[Tiido Priimägi]

R422 will force the video output to be in PAL, so european people can get colors using a Japanese or US machine using RF / composite / S-Vid output. I'm using RGB now, and its no use for me, unless I want to use composite, which I don't. I have US machine and live in Europe.

[KillingBeans]

R422 will force the video output to be in PAL

That's what I'm trying to prove wrong! 

The cool thing about the R422 mod is, that it cures the graphical hiccups you get, when you trie to play the PAL version of cirtan games (like RE: Code Veronica) on a US/JAP machine. These hiccups occur even if you use a RGB cable, and therefor it can't have anyting to do with color coding. It must be caused by something else.. maybe the different PAL/NTSC resolutions?

I seriously (SERIOUSLY!) believe the mod doesn't force the Dreamcast to output anything. From what I can see, it makes the output follow the on disk settings of the game instead (yes I know, I'm repeating myself). Does anybody have some hard evidence against my theory 

[l_oliveira]

There is two things that make the system be pal or ntsc ... the color carrier an the video refresh rate.
If R422 force the PVR chip to run in 60hz then indeed, it might be what "cures hiccups"...

[KillingBeans]

There is two things that make the system be pal or ntsc ... the color carrier an the video refresh rate.

I beg to differ on that. I would say PAL/NTSC is characterized by color carrier and the resolution... not the refresh rate. There is no problem in producing PAL in 60 Hz or NTSC in 50 Hz.

If R422 force the PVR chip to run in 60hz then indeed, it might be what "cures hiccups"...

The refresh rate isn't affected by the R422 mod. You can't change the refresh rate without reflashing the BIOS.

What can I do but quote, what I wrote on DCEmulation.org? :

"When I put a JAP or US game in my R422 modded Dreamcast, it outputs in NTSC.
And when I put a EU game in the same Dreamcast, it outputs in PAL.

Hence my "following" theory.

Is it just me, who's going crazy?"

[Tiido Priimägi]

R422 will make my DC output colors using PAL color carrier freq ... it doesn't matter if I use US or JP game in my DC, it will always display colors in any case (if I use composite / s-vid). The vertical refresh is not affected.

[KillingBeans]

Okay, I guess that kills my theory 

I don't get it. My Dreamcast is a PAL machine that, besides the R422 mod, has been subdued to the region changer mod and has a 4-wire modchip built in. It must be the combination of the three that somehow gives this strange behavior 

[Tiido Priimägi]

You get B/W pic when playing JP/US game ? The R422 mod is unnecessary on PAL machines... and its better to use RGB anyway... or maybe use a PC monitor.

[KillingBeans]

You get B/W pic when playing JP/US game ?

I can't tell yet, since I only got at RGB cable and a VGA cable. But one of my friends has an older TV that needs to be set to either PAL or NTSC, so that it maches the source... even when you use RGB, otherwise the picture will start "rolling". Maybe it just has problems recognizing the resolutions... I dont know.

When we connected the Dreamcast to his TV with a RGB cable, we observed the following:

If the TV was set to "PAL" and we started up a PAL game it went fine, but if we switched to a US or JAP game the picture started rolling. On the other hand, if the TV was set to "NTSC" and we started a JAP or a US game, it went smooth, whereas a EU game made the picture roll again.

This is all that I'm basing my theory on. I know it's not much, and that's also why I need you guys to tell my I'm nuts! 

The R422 mod is unnecessary on PAL machines...

I meant "EU" and not "PAL".. my fault 

I made this mod on it:

http://nfggames.com/forum2/index.php?topic=2639.0

and now it acts like a US machine. That's why I also did the R422 mod 

[l_oliveira]

As far I know, modchips may cause the Dreamcast to behave as a NTSC machine.
And I meant "refresh rate" as the 50/60hz thing (as like with computers where you can program non standard "refrehs rates" on the VGA card because the mordern monitors are multisync)

So the only way to switch the video refresh as Tmee refers as "resolution" (which absolutely isn't the wrong term for it) is fiddle with the Power VR chip registers. Hence having to "flash the bios" as maybe flashing the NOR flashrom where the Dreamcast stores it's regional settings and user setings at a (unprotected) section.

Now that I know your Dreamcast has a 4 wire mod installed, I'm sure that what keeps it from doing the "hiccups" you mentioned earlier is the modchip. 

[Tiido Priimägi]

and I meant refresh rate as 50/60Hz thing too, not as resolution (though in 50Hz the vertical res gets bigger).

And KillingBeans, the rolling seems to be the fault of your TV which won't automatically adjust for refresh change... at least it seems to me.

[KillingBeans]

And KillingBeans, the rolling seems to be the fault of your TV which won't automatically adjust for refresh change... at least it seems to me.

I guess so. I thought the Dreamcast spat out the video i 60 Hz no matter what, since it acted as a US machine, but that's obviously not the case... strange.

And by the way, forget all of my babbling about "resolution". I totally forgot that the Dreamcast always outputs in 640x480... although PAL and NTSC makes different use of the scanlines... well forget about that. The main thing is, that my theory is complete rubbish, and that I don't seem to have a clue, what the R422 mod actually does 

[KillingBeans]

Well, it turned out my Dreamcast was defect. All this time I have been basing my theory on the behavior of faulty hardware 

[AlbX]

Hi to all :-)
I've almost readed fully all this thread :-)
I love the Dreamcast and  i've  probably overpayed it at its glory times.
Mine its a PAL console with modem.
I've played a lot with it using my nice Philips rgb monitor but yes it was hard to play NTSC games ( my monitor always goes out of sync)
I've solved this "behaviour" getting the VGA Box that made me see correctly both PAL and NTSC games ( ehm.. yes my DC isn't modded i've used a BootDisk :ì )
Ciao
AlbX.

[l_oliveira]

A lot of the games released after the boot disc came out had "defensive measures" to counter it's usage.
And for some people swap is pretty annoying.

[AlbX]

Hm yes , swap was and is boring... i think that noone forgot one of the 1st ps2 "mod" that made you play backups manually opening the dvd drive using a "special" tool (a hammer??)
D'oh ,never knew about the "defensive measures" on games, i supposed that the only action was from Sega and the MIL-CD's lock on the consoles..

[l_oliveira]

There were a spring mod for CD Drive lid switch on the 1st gen japanese SCPH-1000.
One could go to the CD Player on the main menu, put the original game disc then the spring.
Once it finished loading the disc would stop. You would swap it with a CDR and exit the CD Player menu it would boot the copied disc.
Serious security flaw...

About the PS2, it was SCPH-10000 and the disc used for swap was the DVD Utility disc which comes with said consoles.