[CrackBerry Question]

I find a problem on my Blod9900,GPS not working.
I turn on all the switch associated with GPS,but GPS does't work at all.
when I press alt+****+H,it says "GPS unavailable"in"OS Engineering Screens".
I get this device a mounth a ago,it's fine at that time.after I changed OS several times ,no working any more.
I try to find answers on the Internet,from China to American,it seems have following reasons:
1:change OS,using the OS with a wrong Mobile telecom carrier ID.the GPS only works when BB match the right ID.BB will lock GPS when it use a wrong OS.
2:software conflict:a software called WeatherEye may cause this problem.

some people says type test in Option->status and run "gps fixing",but if you use a Chinese rom,you'll find it means "start locationing test".
I think the reason one may be the most reason happened on my device ,but I can't find any word of "ID" in my device.how can i find ID?and is this the right cause of my device?
if I can't fix it this time ,I'll turn to my MI MADE IN CHINA.(i get BB9900 with the speaker not working,I fix it finding a piece of capacitance droped )