Were you having trouble from the beginning, or did you install the new firmware and then begin having trouble? I have been reading in other posts that the firmware updated the GSM radio, which is why we can't reflash to an older version without losing mobile internet. My device worked perfectly until the firmware update, so I am wondering what was updated in the radio and if there is a way to fix it. Also, I am wondering if it's specific to T-Mobile or if other carries are having the same issue?