32MB RAM Expansion

[Juan]

Thought you guys might enjoy this. Someone has gotten 32MB RAM running on the Dreamcast

https://tsowell.github.io/2020/06/21/dr ... grade.html

[Juan]

For those attempting to do this, I have uploaded an updated DreamShell CDI image with nearly 50 different BIOS images in a variety of flavors: DreamShell 32MB Flasher
Includes stock BIOS images, Link83, japanese-cake, DreamBoot, DreamShell, etc. A list of BIOS images included here!
This image also contains an updated bflash.klf module to support flashing the MX29L3211 32 megabit chips to accommodate triple-BIOS mods!

Just note before you use this disc that I HAVE NOT TESTED ANY OF THE 32MB HACKED BIOS IMAGES! I simply blindly patched the required bytes in all BIOS images, with no testing at all. I have no idea if any of the other BIOS images will work, especially dreamboot, dreamshell, etc. Make sure you have a backup plan or way to recover your Dreamcast BIOS if you flash one of these and it doesn't work! I plan on doing the mod when I get back from 4th of July vacation. jc-v1.032-32MB.bin has the same sha1 as tsowell's firmware hack so that one should work.

[cube_b3]

I now have a 32MB RAM Dreamcast! I actually got around to getting this done before pulling out for vacation. I had to take a risk in doing a piggyback BIOS install instead of a triple BIOS since my PCBs haven't been made yet -- if any of the BIOS images with 32MB patches didn't work, the DC would have been bricked and I would have had to do some soldering to get things working again.

Luckily, everything I tested WORKS!* I gave my bootROM a good working out today.
(*By "works" I mean the Dreamcast boots up and I am able to launch Crazy Taxi or DreamShell.... I didn't do super extensive testing for each BIOS)
EDIT: Uh oh! Sonic Adventure crashes when loading and Phantasy Star Online v2 crashes when going to the FMV!!! Crap.
Good news is that it is possible to put the pins on a DPDT switch and turn the mod on and off.

Code: Select all

1.004 vanilla						UNTESTED, PROBABLY WORKS
1.01c vanilla						UNTESTED, PROBABLY WORKS
1.01d vanilla						WORKS
1.01d w/ region free patch ("link83")			WORKS		
1.01d w/ region free patch alt intro ("link83")		WORKS
1.01d Treamcast						UNTESTED
1.022 ("no mil-CD BIOS")				NOT INCLUDED ON DISC, UNTESTED
jc 1.300 regular intro					WORKS
jc 1.310 regular intro					WORKS
jc 1.310 alt intro					WORKS
jc 1.032 regular intro					WORKS
jc 1.032 alt intro					WORKS
dreamboot 1.0.0						WORKS
dreamboot 1.0.0 No GD-ROM				UNTESTED, SHOULD WORK
dreamboot 1.0.1						WORKS
dreamboot 1.0.1 No GD-ROM				UNTESTED, SHOULD WORK
dreamboot 1.0.2						WORKS
dreamboot 1.0.2 No GD-ROM				UNTESTED, SHOULD WORK
dreamboot 1.1.0						WORKS
dreamboot 1.1.0 No GD-ROM				UNTESTED, SHOULD WORK
dreamshell boot_loader regular intro			WORKS				
dreamshell boot_loader regular intro No GD-ROM		UNTESTED, SHOULD WORK
dreamshell boot_loader alt intro			WORKS
dreamshell boot_loader alt intro No GD-ROM		UNTESTED, SHOULD WORK
dreamshell sd_loader_with.bios				WORKS

[APE]

Can't figure out my original account's password, think it's tied to a dead email address I turned off. Any chance you can change the password or the associated email address?

If you want a triple BIOS board I have a few unpopulated ones. Have all the parts, will send to you at cost. But it's been over a month so I'm guessing you got the parts.

Aside from the cool factor has anyone made anything to utilize the extra RAM? Or found out why some games aren't compatible with it? I'd be happy to build a few consoles to giveaway to devs if it mean they would look into this.

[|darc|]

Can't figure out my original account's password, think it's tied to a dead email address I turned off. Any chance you can change the password or the associated email address?

I swapped the email addresses on the two accounts, you should be able to activate the APE account with the new email.

If you want a triple BIOS board I have a few unpopulated ones. Have all the parts, will send to you at cost. But it's been over a month so I'm guessing you got the parts.

Appreciate it but unfortunately the triple BIOS board covers up one of the RAM chips so the 32MB RAM mod has to be done first.

I got my boards in but haven't had the time yet to re-do the mod with it.

Aside from the cool factor has anyone made anything to utilize the extra RAM? Or found out why some games aren't compatible with it? I'd be happy to build a few consoles to giveaway to devs if it mean they would look into this.

Unfortunately so far no one has made anything except the ScummVM build that uses it, and the memory testing application.

[APE]

Word, got my account back.

Didn't know that about the mod, haven't done the triple yet.

Shame but it's a start. It's only been a month here.

[Ian Robinson]

I was editing the post while you posted, lol. But I meant to add:

A lot of games have problems running with the mod, so it has to be put on a switch.

Pins 21 and 22 on both chips are connected together, so you should be able to just wire it up with a DPDT switch:

• For 16MB mode wire both pins 21 together and connect them to ground; wire both pins 22 together and connect them where pin 22 usually connects.
• For 32MB mode, wire both pins 21 together and connect them to where pin 22 usually connects; wire both pins 22 together and connect them where pin 23 connects.

Both of these pads also connect to visible vias near the RAM chips, so you have multiple points you can solder to, but the vias are pretty small and annoying to solder.

Since the triple BIOS board covers the RAM chips, you should install like so:

• Remove stock RAM chips
• Bend pins 21 and 22 up on new RAM chips
• Solder new chips in place with pins 21 and 22 lifted
• Wire new chips up using a DPDT switch
• Boot console in 16MB mode and run memtest to verify RAM is soldered properly because this is the last time we can access the RAM on the right
• Add triple BIOS board, covering up the right-side RAM
• While in 16MB mode, boot DreamShell BIOS Flasher disc with 32MB-patched BIOS images I made
• Load up BIOS flasher, flick triple BIOS switch to a writable BIOS bank, write a 32MB-patched BIOS image
• Turn off console, change RAM mode to 32MB
• Boot console and verify with memtest that 32MB RAM is working and seen
• Enjoy ScummVM games with large RAM requirements

I'm not an expert in using any of the PCB design software, but it would be cool if the triple BIOS board with the switching IC were modified so that there were pads for the pins 21/22 of RAM so that the stock bank and bank 1 switch the RAM to 16MB mode and bank 2 switches the RAM to 32MB via one switch.

[APE]

That should be an easy change on that PCB. At this point I don't see much else need for triple BIOS support except for anyone doing dev work with dual compatibility in mind.

[Arvex]

Would I be right to guess that extra 16MB of RAM would be useless for retail Dreamcast games? My intuition tells me it would only be usable if you're trying to boot Sega Naomi ROMs (similar RAM expansion mod exists for the original Xbox to run Sega Chihiro games since they're almost identical hardware) on it or for homebrew games specifically made to use that extra RAM.

[|darc|]

Would I be right to guess that extra 16MB of RAM would be useless for retail Dreamcast games? My intuition tells me it would only be usable if you're trying to boot Sega Naomi ROMs (similar RAM expansion mod exists for the original Xbox to run Sega Chihiro games since they're almost identical hardware) on it or for homebrew games specifically made to use that extra RAM.

I imagine it will be useless for retail Dreamcast games, although perhaps it would be possible to fix something like the unreleased leaked Heroes of Might and Magic III which has out of memory problems.

The Naomi has twice the VRAM and four times the sound RAM as the Dreamcast, so unfortunately it won't be very useful for running Naomi games on the Dreamcast.

Because it's shown to have compatibility problems with existing retail games, and because ScummVM is the only homebrew which supports the mod, I don't imagine it will be very popular, although I really hope homebrew authors include features for it in the future.

[YZB]

I made a kof98 that needs 32M memory to run,

welcome to test, it can be burned or run on gdemu or mode

Warning, dreamcast with 16M RAM does not work

https://mega.nz/file/0aw0nKZB#BI-jp8fIk ... EgN05MjtDY

[|darc|]

Awesome! Thanks YZB! I will have to check this out when I get some time!
From the readme:

Part of the game files are stored in the memory, and the game runs faster (it will be obvious if it is read by CD) I won¡¯t talk about some minor changes.

BTW I love your Saturn RAM cart hacks! I have them on my Saturn with Fenrir ODE

[Arvex]

I imagine it will be useless for retail Dreamcast games, although perhaps it would be possible to fix something like the unreleased leaked Heroes of Might and Magic III which has out of memory problems.

Depending on how it manages memory, you might have to modify the game so it even knows there is more RAM available. It would be cool seeing someone take that unfinished game and not only finish it, but see if there is room to add in the Armageddon's Blade and/or Shadow of Death expansions (HoMM3 Complete is just over a gigabyte installed on my PC, so it might be possible with some compression.)

[YZB]

I made 2 videos, both of which were burned to cdr and read on dreamcast



1 The original game has not been modified, it is suitable for dreamcast with 16M memory

https://www.bilibili.com/video/BV1mz4y1d7um/



2 32M dreamcast is used, and the game has been modified and optimized a lot

https://www.bilibili.com/video/BV14p4y1Y7bE/


3 Use gdemu to read the original gdi, 4Gsdhc memory card
https://www.bilibili.com/video/BV1at4y1v7bH/



4 Use gdemu to read 32M memory version of gdi, 4Gsdhc memory card
https://www.bilibili.com/video/BV1HV41127sT/

[YZB]

I modified a new game to support 32M memory
Because this game is relatively simple to modify
The current effect is that after entering the game, except for the music of adx which needs to be read and played, there is no need to read data at any time. It runs completely in the memory.

Welcome to test, please note that it can only support dc with 32M memory, if not, it will show a warning screen to remind you

https://mega.nz/file/tX4EgaRS#H6O9JhIVd ... K5ABKdphp0

[Calavera]

This is pretty neat. Even though there isn't much use for it at the moment it is just cool that it is even possible. Would it be possible to go higher than 32MB or is that the limit? If the Dreamcast has originally launched with 32MB of ram how much of an improvement would it been for games? Sorry if this is a noobish type question. Lets use a high quality game like Shenmue or Shenmue II for example. If the Dreamcast would have had 32MB of ram what kind of improvements would it have brought to those games?

[|darc|]

This is pretty neat. Even though there isn't much use for it at the moment it is just cool that it is even possible. Would it be possible to go higher than 32MB or is that the limit? If the Dreamcast has originally launched with 32MB of ram how much of an improvement would it been for games? Sorry if this is a noobish type question. Lets use a high quality game like Shenmue or Shenmue II for example. If the Dreamcast would have had 32MB of ram what kind of improvements would it have brought to those games?

I don't know for sure, but the way tsowell has it wired up, it's 64MB of RAM but the Dreamcast can only "see" 32MB. It might be possible to get more by using a different row/column configuration, wiring it up differently, and changing the AMX bits in the BIOS, but I don't pretend to understand it well enough to know if that's possible.

Had the DC shipped with 32MB RAM, it would have done a lot better holding its own against the PS2. The DC's RAM limitations prevented it from running games like GTA3 with larger, more open worlds. If you look at some of the games that were far in development but never released, like Half-Life and Heroes of Might and Magic III, there would have been tremendous benefits. Half-Life on DC is known for its very frequent pauses to load new areas, and more RAM would have cut down on the constant loading. HMM3 was axed because it runs out of memory and crashes, so having double RAM would likely mean that title would have been actually published. As for Shenmue I & II, it likely would have enabled larger city spaces like GTA3. They did a good job of making Shenmue I&II feel like a large world in the pre-GTA3 days, but even though GTA3 is an uglier game than Shenmue I&II, it has way more freedom to explore and do random things in what feels like a real open world.

[YZB]

The third 32M memory version game I uploaded

Knights of Valour The Seven Spirits

Warning, it can only run on a dreamcast with 32M memory. After decompression, the cdi is only 50M (so it cannot be burned). Please use usb gdemu usb to test on a 32M memory Dreamcast

https://mega.nz/file/0GoiTZja#jNwgPBkXU ... LldhuY6PdA

video test：
https://www.bilibili.com/video/BV12K41137xi/

[donnonotin]

Wow, I would like to see this to load some kawaks or Final Burn Neo. I remember it was hard to emulate Metal Slug because of RAM

[YZB]

The 4th 32M game 32M memory version game （Upload later after testing ）

King_of_Fighters_XI_for_32M

Original video（naomi2+gdi）thanks carlosxi upload：
https://www.bilibili.com/video/BV1hU4y1x79J/



hack 32M（GDEMU+GDI）
video test：
https://www.bilibili.com/video/BV1rr4y1P71V/


down：https://mega.nz/file/NpU3DSCY#Kq669Gejt ... ibdFDU6ZA0

Welcome to test