It may be. I know after modifying my clip, I usually get valid dumps first try. On all models. Including that one.
When you press the clip down, look to see the clip is flush with the mobo. I bet there is a gap on the side with the transistors.
Updating the flasher, shouldn't matter on getting a valid dump. I have my flasher updated with the Samsung 10.28.2011 update.bin. Because it allows for multiple consoles.
That update also is compatible with all nor chips. So a newer update.bin is not the problem.