I dont know if this is well know or not but if you have a custom rom weatherpanel could make your device lock at the third bootscreen You can find more info here:
http://forum.ppcgeeks.com/showthread...t=weatherpanel.
A work around that MIGHT work here:
http://forum.ppcgeeks.com/showthread.php?p=321056.
I was hit with this problem so now im just gonna use Swcked weather. Really sucks I really wanted those awesome 3d graphics.