i live in philly area too, got brand new evo 2 days ago, got the ota and 4g would not connect at all, called for support went to three levels of Sprint Support the sprint people are so STUPID they kept telling me that the service was listed as in building which meant that they were building out. I pointed them to the explanation on thier web site which said in building meant reception in building, I also pointed them to coverage map which showed I was in area of best reception. they still did not get it. so they put in a ticket to thier network swat team, which takes up to 48 hours. I did not want to wait that long and I went to sprint repair store , I figured that they could not tell me that thier store was not in coverage area, as all stores have repeaters. The repair guys had it for 45 minutes and could not figure it out. 5 minutes later they came out with new evo, I made them show me 4g working, told them do not apply ota. a few hours later engineer called on phone to work i ticket, I told him prob solved, i got a new phone.
My guess is that the ota fix, screws up either password, or mac address to connect to clear wimax service.
.......sorry for that but i had to rant