Unhappy [Q] Locked BL updated to latest OTA

I was using original stock 4.1.1 version + http://forum.xda-developers.com/show...light=98+18+94 to use xt907 on t-mobile.

Yesterday, I used RSD to restore the 4.1.1 version and OTAed to the latest 98.30.1.XT907.Verizon ROM. Then the t-mobile sim does not work any more, and the original method does not work.

Then I tried to downgrade 4.1.1 version using RSD, and failed. Then I'm stuck in the fastboot mode...

My question is:
1. Is there a way that I can get out of fastboot mode? Which rom should I use in RSD to restore?
2. Is there a way that I can downgrade to earlier version?
3. Is there a way that I can still use t-mobile sim card?