LG G2 EFS Backup Zip
The G2 has no built in EFS backup partitions. EFS contains things like your MEID or IMEI... your data profiles.. radio settings. The EFS cannot be replaced... it is unique to your phone only... backing up your OWN EFS is highly recommended.
I have added EFS backup to the IOroot scripts so that everyone that roots will have a copy of their EFS partitions on the computer you run IOroot from. Regardless, this current thread will still be a good "heads up" and an alternative for those who insist on using other shady root methods or for those who just want another way to back things up.
Backing up EFS
In TWRP, flash the LG_G2_Backup_EFS.zip attached in this thread. LG_G2_Backup_EFS.zip creates a flashable zip backup of your EFS in /sdcard/EFS_Backup/. Please check to make sure the backup zip worked and actually made a .zip file. Any issues please list what recovery and version you are using and please post the recovery.log.
Backup your efsbackupflashable.zip somewhere else besides your internal SD!!! Email.. cloud.. PC..
To restore your original EFS just boot into recovery and flash the efsbackupflashable.zip in your /sdcard/EFS_Backup folder.
If flashable zip wasn't created or to manually restore efs img files run the following commands using adb shell while in recovery:
dd if=/sdcard/EFS_Backup/efs1.img of=/dev/block/platform/msm_sdcc.1/by-name/modemst1
dd if=/sdcard/EFS_Backup/efs2.img of=/dev/block/platform/msm_sdcc.1/by-name/modemst2
Backup ALL Partitions
Well almost all... I am attaching another zip which backs up most of your phones partitions.. excluding system/data/cache and some other useless partitions. Backing up all partitions isn't as important as backing up the EFS but it can't hurt. Never know when you may need it.. especially those who like to poke around with their phone and try new things.
Run the zip in recovery.. it will make backup .img files on your internal sdcard in a new folder named "backupz"... remember to copy your backups off the internal sdcard.