Same issue with the new official Sprint rom. Strange, I was able to get it past the loading screen by actually turning the screen off and on repeatedly, and once I screwed around in that fashion...the program became more and more responsive until it worked fine. This was WITHOUT "priming" the GPS (I typically use TGPS to start up the GPS).
I plan on playing around with it more to see if there is another way to get it working properly from the start.
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I reset the device, loaded up TGPS, loaded iGO up, and it started up immediately.