(news & commentary)
The Magic Lantern project, which hacks Canon firmware to expose and add new features, has made it to the EOS M in "alpha" form. Early experiments date back into late last year, but we're now at a stage where the hack seems to have some reasonable benefits and is mostly stable. The current software can be downloaded at the Magic Lantern site.
Canon cameras are unique in a couple of ways. First, Canon has often left code in their firmware that isn't implemented at the user level. A company does this to differentiate product but keep their code base as close as possible amongst models to minimize creating new bugs when creating new cameras.
But the Magic Lantern hacks go further and use another of the Canon's unique attributes: the Canon cameras can execute code that's on storage cards. Thus, there's been a great deal of experimentation on Canon cameras trying to figure out how to access the "black box" (i.e., the DIGIC imaging ASIC) in interesting ways. Often the ASICs have abilities that aren't used in the camera firmware, or at least have options that aren't being used by the camera. The good news here is that, unlike the Panasonic GH2 hacks, you don't have to replace your camera firmware to use the Magic Lantern code. The potential bad news is that bad external code could change variables stored in NVRAM on the camera, and a wrong value could cause the camera's regular firmware to complain or fail. Hacks always come with a bit of risk, though the risk appears minimal with Magic Lantern hacks.
The net result is that the Canon cameras are the best targets so far for the firmware code experimenters, and the Magic Hack projects have created a lot of interesting new abilities. What kind of capabilities? Well, bit rate improvements in the video stream, RAW video (a slight misnomer: really only uncompressed video), HDMI out while shooting video. It's not clear whether all of the usual Magic Lantern features are working yet on an EOS M, but those include other things like focus peaking and zebra production.
You'll note that most of those things are video related, just as with the Panasonic hacks. The video crowd still wants large sensor cameras that can be put into small spaces and generate pro-level output. The EOS M obviously has the first two (large sensor, small camera), so it's the output that's getting a lot of attention, same as it was with the GH2.