32MB RAM expansion

By replacing the Dreamcast's two 8MB SDRAM chips with larger SDRAM chips, modifying the pin arrangement, and modifying the BIOS, it is possible to install 32MB of RAM in the Dreamcast. Existing games and applications will very likely not be able to address the RAM, but applications built with a patched version of KallistiOS are able to address all 32MB.

At the moment, the only known software able to take advantage of the 32MB RAM expansion is the Alternate ScummVM backend for Dreamcast by tsowell. This version of ScummVM also offers an extensive array of other expansion hardware features, such as compatibility for loading/saving data with SD cards and hard drives, the ability to output MIDI over serial or the expansion slot for external synthesizers, and the ability to output various VGA modes for CRT monitors.

32MB-patched BIOS image testing

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 1.300 alt intro	UNTESTED, SHOULD WORK
jc 1.310 regular intro	WORKS
jc 1.310 alt intro	WORKS
jc 1.320 regular intro	WORKS
jc 1.310 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 GDROM	UNTESTED, SHOULD WORK
dreamshell boot loader alt intro	WORKS
dreamshell boot loader alt intro No GD-ROM	WORKS
dreamshell sd_loader_with.bios	WORKS

A DreamShell image with 32MB patched BIOS images is available. This image contains a variety of nearly 50 BIOS images including the stock BIOS, japanese-cake BIOS, DreamBoot BIOS, and DreamShell BIOS, in a variety of flavors for each. This image also contains an updated bflash.klf module to support flashing the MX29L3211 32 megabit chips to accommodate triple-BIOS mods!

• *WARNING* While most of the BIOS images on the disc have been tested, not all have. See the testing chart to the right. "WORKS" means that the Dreamcast boots up while using this BIOS and boots DreamShell and/or Crazy Taxi. There is a high likelihood that some games will exhibit bugs. So far, bugs have been noticed in Sonic Adventure and Phantasy Star Online v2. More testing to come.
  • Seriously! We are not responsible for damage to Dreamcast units due to the use of this disc. Know what you are doing before you use this disc!
    • Download DreamShell 32MB BIOS Flasher Image

• A memory testing utility is available as well. File:Memtest.tar.gz

See tsowell's blog for more information on the modification for now.