My Iphone was previously jailbroken with Spirit and I unlocked it successfully yesterday with UltrasnOw. I had the same issue others have mentioned where Cydia showed an Ultrasn0w update outstanding which I ignored. I have been using T-Mobile since the Unlock. Today i saw that there were three updates outstanding on Cydia 1. was the Ultrasn0w 2. was mobilesubstrate and 3. was mobile terminal. I decided to do the update for mobilesubstrate and mobile terminal one at a time. The mobilesubstrate update showed completed but left the phone spinning out of control where i could not recover. The only way I could get out of it was to put it in DFU mode and restore. Fortunately i have my SHSH blobs saved and was able to restore to 3.1.3 and 5.12.1 which I am now in the process of JB and unlocking again. I will be in no hurry to take any more updates from Cydia. Put this out there so others may be careful if they see mobile substrate updates outstanding.