[Samsung Galaxy Note 8 Guides, News, & Discussion] bluecub1st:
The following is a guide for repairing failed to mount efs and dm-verify fail (drk error)

We finally did it ~~~:D:D:D:D

Warning - We will not take any responsibility for your device. Follow the steps at your own risk. If your device is Knox 0, This guide would convert it into Knox 1 due to TWRP. For solutions that does not convert to knox 1 check out payed remote solutions. Everything on your device will be reset, including efs partition. You will need backup of efs.

Test on N950F binary 4 may work on other exynos models comment below if it worked for other samsung devices.

Problem Detail -

Bootloop with samsung stock firmware boot logo.

Recovery error E:Failed to mount /efs (Invalid argument) or dm-verity verification failed...

Device cannot boot into Factory binary or Stock Rom​

Actions that could cause this problem -

Flashing a non-signed efs.img by odin

Corrupt flash of efs partition.​

Note - Must have efs backup for device to work (very important)

Any error that cause bootloop would show in recovery required if

Files Required

Latest Odin (recommend 3.13)

Working Stock firmware and Combination file (same binary as bootloader)

PC

Winrar or 7zip etc

Solution for efs failed bootloop-

Extract Stock firmware AP file (rename .md5 to .tar)

Rename dqmdbg.img to efs.img (or smallest image must be smaller than 8000 KB). Extract Dqmdbg.img.lz4 so it’s just “Dqmdbg.img” and then rename it to efs.img and put that one in a tar. Other option is downloading a file that’s already made this way if your bootloader is binary 4, Saves you trouble of extracting / renaming: http://www.mediafire.com/file/589wucja9rk2v8f/efs.tar/file (if you download this file just move onto number 3)

Add file new efs.img into tar archive.

Flash tar as AP file in odin + download mode

Reboot download mode

Flash Combination with odin + nand erase option on Edit: suggest you to flash stock rom first and oem unlock, don't need to wait for 7 days if imei is 0000 skip combination step

Device Should boot into Factory binary

Use IME to restore imei using *#06# (or imei 0000 in stock rom) Edit: This step is not required if efs backup is restored successful

Your device should have dm-verify failed in recovery due to drk error

Continue drk bypass for dm verify error below to continue

Solution for dm-verify error (also known as drk bypass - but temporary read note)-

Extract Stock firmware AP file

Make a copy of boot.img and delete recovery.img

Note - if files is boot.img.lz4 format change name to recovery.img.lz4

Rename boot.img copy to recovery.img

Add all the files (including other files extracted) to tar.

Flash Modded AP file with BL, CP, CSC (nand erase not required)

The phone will boot into stock firmware

Note- cannot reboot, will stuck at dm-verify error again and need to flash modded AP again.

Wait 7 days to oem unlock phone or use 7 day bypass by changing dates (not always work, keep trying, don’t reboot, worked for Samsunguser932 Edit: Imei must be 0000)

Edit: oem unlock will fix drk - if not you must follow next step

Once oem unlock flash TWRP and restore efs backup Edit: if you haven't fixed imei fix now by *#06# with combination file

Flash stock firmware once again by odin (stock, not modded)

Done - phone is back to normal

If you cannot be bothered doing by yourself you can pay https://www.facebook.com/gsm.xraxxx/ to do this.

(after he used plexihub to fix phone, i believe he is using similar method. It doesn’t seem fair to post this guide as i’ll be damaging his income but it seemed also unfair to keep this as a secret. If you want to donate to me please donate to him and his team instead at https://spacial-file.com/ or paypal rkunlocker@gmail.com Thx)

Special Thanks to -

Samsunguser932 - testing this guide you can see his post on https://xdaforums.com/galaxy-note-8/help/note-8-phone-booting-efs-restore-t3830209

Ravi Kumar - for his help in giving me clues how to fix.

Resources: (where i got most my info)

https://xdaforums.com/galaxy-note-8/help/unbrick-methods-t3703767

https://xdaforums.com/galaxy-note-8/help/to-fix-efs-secondary-note-8-t3785600

https://xdaforums.com/galaxy-note-8/help/note-8-phone-booting-efs-restore-t3830209

http://forum.gsmhosting.com/vbb/f453/samsung-s8-g955f-2426383/​

Comment below for help.

Give me a thanks if you find this guide very/extremely helpful. :angel:

Share it with those in need.

edit: not all images were able to upload

update: to skip 7 day oem unlock imei must be 0000