Backup OnePlus One EFS Data (Restore It When SIM Not Detecting Issue Occurs)
If you are one of those who often tryout custom ROMs on your OnePlus One, you should take care of EFS data of your device, because EFS data contains all networks related things such as IMEI number, Wireless MAC address, baseband version, etc. Once it is lost, you will not be able to use your phone on any mobile network. Also, you cannot use Wi-Fi, Bluetooth, etc. Therefore, you should always make a backup of the EFS data before installing a custom ROM.
