used both Odin and SD card. there is a thread on AC where other people are having similar problems. it has been a rare problem (we are the only 3 people I've heard of it happening to), and it is something I believe is something hardware related as far as bugs go because there are lots of time where I lose 3G ANYWHERE I go and it won't come back until it decides it wants to(prl update, profile update, battery pull, etc., all fail).
it's been speculated that perhaps this is why the official froyo update is taking so long. this is my third Epic, and DK28 didn't come out until my second Epic. i had to get that one replaced because something got borked in that one where it wouldn't update my profile or prl no matter WHAT was done, so they replaced. that phone ran DK28 fine, but this one behaves as shown.