[p2k]

i've had similar problems, and I've noticed that I only get it when i go from WM6.1 to WM6.5.

6.1 to 6.1 has no issues at all... but everytime i go 6.1 to 6.5 i get the random freezes.

I got MR5 on my phone after 2 attempts... This is how i did it...

Flash to stock... wait for tap to begin screen calibration screen then pull the battery...
wait for it to come up again... then it will connect to Activesync(I dont bother aligning the screen or the customization)., and i flash it to MR5.

Again i wait for the tap to begin screen, and I pull the battery again...
Then I go ahead with the screen alignment.