I would uninstall ML first then do the reset.
Something must have gone wrong with my ML install. ML website says to uninstall ML from firmware update in menu, but when I try to uninstall ML by going to Wrench menu=> "firmware version"=> then I get the message "Memory card containing firmware is required to update" even though the memory card with ML files is still inside the camera.
I don't get the "instructions" ML website says should show up. What am I missing? Should I just go to "Format card" and choose "Format card. remove ML" option? If I do that, my understanding is the bootflag in camera body is still not deleted.
I formatted the card, set the camera to factory reset ("Clear Camera Settings"), then reinstalled ML, and this fixed my auto image preview problem and the ML uninstall option shows up in "firmware update." I was also happy to see clearing camera settings did not erase my C1-C3 custom settings or AFMA values.