We actually posted this to our Facebook page yesterday (which has since been picked up by others) but wanted to share the information here as well - along with a few very important caveats. On "M9 class" cameras, that is: M9, M9-P, M Monochrom and M-E - you can enter factory service/debug mode with a particular button sequence, revealing a host of options from explicit firmware details, testing the rear LCD with an RGBW sequence, to tweaking particular bits on or off and more... The meaning of which only Leica Camera knows for sure (we don't).

The sequence to enter this factory service mode with the buttons on the back of the camera is as follows:

Delete -> up (2x) -> down (4x) -> left (3x) -> right (3x) -> Info

Now of course, the important caveats regarding this. First, we highly recommend you not mess around in here. At best, you might inadvertently (and detrimentally) affect your camera's operation and at worst, you could brick your camera. Furthermore, actions performed while in this mode may be recorded. When the camera is sent in for service, this will very likely void the warranty and you will be charged a hefty fee for further service. So it goes without saying that you should do this at your own risk.

One very interesting value is NumExposures, which shows the number of shutter activations of the camera. It is accessed through the "Body Debug Data" menu option and scrolling down. Of course, this will likely become quite popular, especially when buying/selling used bodies. This method can be replicated in a safer fashion by using the m9info program.

It's worth noting that this sequence does not work on the Leica M (Type 240). But it's surely similar.

Screenshots

For those curious, this is what it looks like, as seen on an M Monochrom with the latest firmware as of this writing (v1.002). It looks the same on the M9, also with the latest firmware (v1.196). Apologies for the lousy quality, but they get the point across: