OnePlus One (A0001) Device No IMEI / EFS Backup Problem Fixed
So You are facing No IMEI Problem With your Device and No Network.
Then you are at Right Place to Solve this ISSUE, i've read some post on xda that flashing
"COLOR OS" May Fix this ISSUE (Worked only for Some Users but not all).
First You Have to Flash TWRP Recovery on Your OnePlus One (Only If u Don't Have)
Unlock Bootloader (If you do not)
Download Below Files
Install ADB/Fast Boot
Open a Command and TYPE
- fastboot erase persist
- fastboot flash persist persist.img