[LG G2 Mini] powermetza:
For those who do not know, EFS partition containing IMEI, MEID, and other important data. Once lost, these partitions can not be recovered, because they are unique to your phone only.

Since we do not have a custom recovery yet, the only solutions to backup EFS partitions are in terminal or adb. I prefer adb because it is more easier to do.

1.Create a folder in internal sdcard named efs

2.Run these commands in adb or terminal

dd if=/dev/block/platform/msm_sdcc.1/by-name/modemst1 of=/sdcard/efs/modemst1.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/modemst2 of=/sdcard/efs/modemst2.img

3.If you want to backup all partitions on your phone create a folder named backup in internal sdcard can run these commands:

dd if=/dev/block/platform/msm_sdcc.1/by-name/aboot of=/sdcard/backup/aboot.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/boot of=/sdcard/backup/boot.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/DDR of=/sdcard/backup/DDR.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/encrypt of=/sdcard/backup/encrypt.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/fota of=/sdcard/backup/fota.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/fsc of=/sdcard/backup/fsc.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/fsg of=/sdcard/backup/fsg.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/laf of=/sdcard/backup/laf.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/misc of=/sdcard/backup/misc.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/mpt of=/sdcard/backup/mpt.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/persist of=/sdcard/backup/persist.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/rct of=/sdcard/backup/rct.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/recovery of=/sdcard/backup/recovery.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/rpm of=/sdcard/backup/rpm.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/sbl1 of=/sdcard/backup/sbl1.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/sns of=/sdcard/backup/sns.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/ssd of=/sdcard/backup/ssd.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/tz of=/sdcard/backup/tz.img

Less important partitions:

dd if=/dev/block/platform/msm_sdcc.1/by-name/abootb of=/sdcard/backup/abootb.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/cust of=/sdcard/backup/cust.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/drm of=/sdcard/backup/drm.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/eksst of=/sdcard/backup/eksst.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/factory of=/sdcard/backup/factory.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/grow of=/sdcard/backup/grow.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/modem of=/sdcard/backup/modem.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/pad of=/sdcard/backup/pad.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/rpmb of=/sdcard/backup/rpmb.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/sbl1b of=/sdcard/backup/sbl1b.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/sdi of=/sdcard/backup/sdi.img

dd if=/dev/block/platform/msm_sdcc.1/by-name/tzb of=/sdcard/backup/tzb.img

For dd commands your phone has to be rooted.

Please do not ask me how to install and use adb.

If you want to restore your original EFS partitions just run the commands below in adb ot terminal:

dd if=/sdcard/efs/modemst1.img of=/dev/block/platform/msm_sdcc.1/by-name/modemst1

dd if=/sdcard/efs/modemst2.img of=/dev/block/platform/msm_sdcc.1/by-name/modemst2

You'll have to type that whole thing out, and be VERY careful with spaces and punctuation. One wrong letter and you could hard brick your phone.