Drivechip

From WiiLi

1 What is a drivechip?
2 How does it work?
3 Drivechip Detection
4 Compatibility Problem
5 List of Drivechips

[edit] What is a drivechip?

A drivechip is a very simple hardware modification that alters the way the Wii's optical drive works. It is connected directly to the optical drive motherboard and does not interface with any other component in the system.

[edit] How does it work?

The optical drive found in the Wii is capable of dealing with normal DVD media. But the drive's firmware is only programed to work with genuine Wii media.

Normally, the firmware checks if a disc is a genuine Wii disc by looking at certain areas of the disc like the BCA (Burst Cutting Area) and the DMI (Disk Manufacturing Information), and refuses to work if the checks are not passed. Also genuine Wii discs use custom scrambling seeds that must be properly initialized.

A drivechip takes control of the optical drive's firmware by patching it though a series of debug commands. It, at least, modifies the scrambling seed initialization and the layout of read sectors to match those of standard DVD media. (Note that this is no different than what any other mods do).

What makes a drivechip special is the way it sends the above mentioned debug commands to the optical drive. It uses a serial port from where the original drive firmware allows receiving a small subset of serial commands, including some debug commands. A drivechip will typically patch the drive firmware using serial commands when the drive is reset, making it transparently interoperable with standard DVD media.

The hardware needed to send serial commands and to store the firmware patch (and the optional apploader patching code) can be implemented easily and with very cheap components. In fact, the bill of materials for a drivechip is rumoured to be as low as 7 dollars [confirmation here, i presume it is even cheaper].

[edit] Drivechip Detection

There's a very popular myth concerning the current Wii drivechips: many people believe that it's technically impossible for Nintendo to detect them. People who believe this will usually mention reasons like "they don't even modify the Wii or the DVD-Drive-Firmware, so they can't be detected!". The fact that the Wii drivechip makers solicit their products with buzzwords like "Stealth" supports this myth as well.

But fact is: At the latest when you're running a backup disc, ALL the current Wii drivechips can theoretically be detected. In fact, it would be quite easy for Nintendo to do so.

All current Wii drivechips work by connecting to an unused serial debug port of the DVD drive controller (that's that DMS/D2A/D2B thingy you've heard of). This debug port can for example be used to read/write to the RAM used by the DVD controller, and that's exactly what the current drivechips do: To make backup discs work, these drivechips must modify the DVD controller RAM in some way. Now what makes the drivechips detectable is that the Wii can read/write that RAM too (in fact even gamecube software can do that - just remember how GCOS can read your DVD drive date/version, or how gamecube homebrew discs can be used to update the drivechip firmware), so it can check for any unusual changes in the DVD controller RAM that can only be caused by a drivechip. Maybe the easiest way of doing so would be to check a special memory location that unlocks the DVD controller memory. About the first thing ALL current drivechips need to do to get backups running is to write the value 0x41 to that memory location. Check the source of dvdtool or any open source modchip you like and you'll see that it's true. Periodically checking that special memory location for that special value would be enough for Nintendo to detect all current drivechips. There would be no way of tricking that mechanism in order to get backups running. And so what ? This IS the value the wii firmware MUST read when an original game is inserted, else it won't play. In my opinion, it isn't a way for nintendo to detect a modchip.

Starting with Wii firmware version 3.0, firmware updates are accompanied with a warning message that the update might "cause inoperability" if the Wii has an "unauthorized technical modification". Chances are this message just appears to warn owners of modded Wiis about the risk of bricking their console when running a different-region game that tries to install a different region firmware update. But with Wii drivechips being out for six months now, the risk that a new firmware update is indeed capable of detecting drivechips is growing and growing; if Nintendo really wants to fight modchips, they should have been able to develop effective strategies by now - the example above shows how easy it would be. And remember, a newly released firmware update that doesn't seem to affect modchips can be deceptive; remember how Microsoft waited for months before they banned owners of modded 360s.

So if you think about updating the Wii firmware to versions >= 3.0, remember that there always remains a chance that they are not really mod-safe.

[edit] Compatibility Problem

There seems to be a snag with early Drivechips for the Wii. It seems that they do not work on newer Wii units shiped in January and Feburary of 2007. In these newer Wii units, a D2B Panasonic chipset is being use. You can find the chipset in your Wii by opening it up[1], or by the serial number[2].

Both the CycloWiz and Wiinja teams know of the compatibility failure and are working on fixing it.

Update: the problem has been fixed in new versions of Wiinja, Cyclowiz and Wiikey. Be sure that the one you order is "D2B" compatible.

[edit] List of Drivechips

[edit] Openwii

Openwii is an open wii chip that is Upgradeable via DVD and can play other region games without patching, just like commercial ones! It's website is a bit messy, but did I mention that it's free?

[edit] Chiip

Chiip is an open-source drive chip that you can build yourself for just 2,38€ (to build a programmer costs 0,94€). There is a very detailed guide on the page and since you don't need PCBs neerly everyone can build it.