This has been over the last two versions that I've tried, and after many repeated attempts to format/try again.
Essentially, I have a UDMA 7 compact flash, and I am installing ML on my eye-fi 8gb sd card.
Sometimes it boots up, no worries. Others, I turn the power on and nothing. When this happens, I must pull the SD card, pull the battery, start the camera, then while it's still on, open card door, and try putting SD back in. 50% of the time, this works, and the other 50% it never resumes, causing the battery pull maneuver again and again.
Feels uber sketchy and has me worried. :/
Also, if I leave the SD card in the camera, even with the camera off, it drains the batteries in a matter of hours (less than a day).
Frankly, I got plenty of error 80's with the eye-fi, so I am not ruling that out as the culprit, but I'd like to pursue all other avenues first.
If there's anything I can do on my end to help solve this which might prevent the issue for others, let me know. Happy to help, and she's insured. ;)