XBOX enthusiast and modder, Prehistoricman, has found a way to modify 1.6 XBOX revisions with 128MB of RAM. Now, why is this noteworthy you may be asking? The 1.6 revision of the XBOX was the last motherboard revision that Microsoft manufactured. And, it differed from previous revisions in a few ways, but most notable was the lack of the extra 4 unpopulated footprints for additional RAM chips.
XBOX revisions prior to the 1.6 had four unpopulated footprints that allowed for memory expansion, up to 128MB. These footprints existed because Microsoft used the same motherboards in XBOX Debugging units as well as the Sega Chihiro Arcade system, both of which utilized 128MB of RAM.
For a while, modders have been upgrading the RAM on 1.0-1.5 revision XBOX consoles, but neglected the 1.6 because it was deemed impossible. To get around the 1.6’s lack of extra RAM footprints, Prehistoricman decided to use an age old technique called Piggybacking, which is essentially stacking the RAM modules on top of each other to expand the usable memory. This is method works because the each banks of RAM share the same data lines on the older motherboard revisions, and stacking the RAM modules is effectively achieving the same thing.
By stacking the RAM modules on top of each other and soldering the legs in parallel to the original RAM chip, we are now able to double the RAM of 1.6 XBOX consoles. The only caveat is that pin 28 on all added RAM chips need to be lifted and wired to the GPU. Pin 28 is the “chip select” pin which allows the XBOX to identify each RAM module and address is appropriately.
Now that the 1.6 XBOX is modded with 128MB of RAM it can do some pretty neat tricks such as play some Sega Chihiro arcade titles, be used as a debugging unit, play patched XBOX games which can run at a higher resolution etc.
For a more detailed deep-dive on how this mod works, check out Prehistoricman’s video:
And you can find Prehistoricman’s original post for this mod on the OG XBOX Forum.