I have a AT&T sgh-i747. I wanted to try CM 11 so I installed CWM and made a backup with ROM Manager, which is a nandroid backup if I'm understanding correctly. I installed the latest snapshot of CM 11 and did not have data access. or lte. I flashed the newest modem from this link : http://forum.xda-developers.com/show....php?t=1831898 and then I had no ability to place calls or data. Tried several different modems from the list to no avail. I tried to set up the AT&T APN settings but no matter what I did the settings would not save. I flashed an older snapshot of CM 11, nothing changed. After hours of frustration I decided to revert back to my stock nandroid backup which is 4.4.2. I installed the backup via CWM recovery but now I have a no sim card error and "com.google.process.gapps has stopped working" constantly popping up. My phone is now completely useless. Have I bricked this thing or is there just something I'm missing and not doing correctly? The baseband version is listed as unknown. Please help! I do have another motherboard for this phone that has a working stock version of jellybean installed but It seems to have some hardware glitches so I installed the new motherboard. If I needed to I could reinstall the old board and pull files from it. Any help is appreciated!