[GUIDE] FIX N950F efs failed to mount and dm-verify fail (unbrick) - Samsung Galaxy Note 8 Guides, News, & Discussion

The following is a guide for repairing failed to mount efs and dm-verify fail (drk error)
We finally did it ~~~
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 [email protected] Thx)
Special Thanks to -
Samsunguser932 - testing this guide you can see his post on https://forum.xda-developers.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://forum.xda-developers.com/galaxy-note-8/help/unbrick-methods-t3703767
https://forum.xda-developers.com/galaxy-note-8/help/to-fix-efs-secondary-note-8-t3785600
https://forum.xda-developers.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

---

The best method for bypassing oem unlock for 7 days.
Requirements - clean phone with stock firmware, samsung account logged in, imei 0000
Go to setting and check for manual update. This will fail/stuck and oem unlock would appear in development settings

---

Reserved

---

hello , i have samsung j737t with bad efs ,
Recovery error E:Failed to mount /efs (Invalid argument)
any help please ,i have cert in hand

---

maxpatri9 said:
hello , i have samsung j737t with bad efs ,
Recovery error E:Failed to mount /efs (Invalid argument)
any help please ,i have cert in hand
Click to expand...
Click to collapse
Try the above guide. This guide isn't just designed for the note 8.

---

from what file i need to create efs.img for s8+ g955F?

---

ditternation said:
from what file i need to create efs.img for s8+ g955F?
Click to expand...
Click to collapse
You do not need an efs.img to repair efs failed to mount. It is only required for the functionality of the phone (sim). This guide would work without an efs.img, it is recommended to install a custom rom after the guide. Even though this guide can allow you phone to work, but due to drk/dm-verify errors, it is currently impossible to restore the phone to the original state.
Note - you'll need to find someone that is kind enough to share a copy/backup of their efs.img g955F. Most people think it is illegal to share as the efs.img contain imei, but with cpid devices, the imei would be overridden by your current device. Most importantly you need to change the serial number in the SVC (or else you will have the same serial number as the person sharing.

---

plz my problem is oem lock on, frp on and drk error. i have combination file and stock can your guide work for me?

---

soundn said:
plz my problem is oem lock on, frp on and drk error. i have combination file and stock can your guide work for me?
Click to expand...
Click to collapse
This would only work if you're still on binary 3. Follow the steps for DM verity fix with 7.1.1 firmware. Flash stock 7.1.1 with replaced boot.img using Odin and fix frp using adb (guides online to enable adb). Wait for 7 day OEM unlock (no method to skip do not restart). Flash twrp and use twrp to flash custom ROM or DM verify fix.
Note - this method would fix function ability of the phone only if efs is not corrupted. (If you had paid someone to fix efs, this would not work). Finally the phone will become Knox 1 and normal update functions might not work. Practically makes the phone unable to resell as a working phone.

---

Hello. My efs partition was erased by a z3x box. Or an octopus, I do not know. I followed your instructions. The IME combination is empty. I install a modified firmware, it works but I can not enter the Samsung account (crashing), I can not check the system updates (infinite device registration). Should I wait 7 days before the OEM unlock? Will it work?

---

@Alarg read post 2 to skip 7 days. Infinite device registration should make OEM unlock show with samsung account logged in. OEM unlock must be first done before installing modified firmware (suggest kernel). You must have backup of efs, a backup from another phone will not work.

---

bluecub1st said:
@Alarg read post 2 to skip 7 days. Infinite device registration should make OEM unlock show with samsung account logged in.
Click to expand...
Click to collapse
I can't log in Samsung account (processing failure). Imei unknown, s/n 0000000000 This method does not work for me.

---

@Alarg Which firmware ver are you using?
Have you tried nand flash combination file and then flash firmware (before boot, hold download mode buttons so the phone won't boot to factory mode). I do not see a reason why Samsung account would not work, try another ver maybe the version you downloaded is corrupted.

---

bluecub1st said:
The following is a guide for repairing failed to mount efs and dm-verify fail (drk error)
We finally did it ~~~
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)
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 [email protected] Thx)
Special Thanks to -
Samsunguser932 - testing this guide you can see his post on https://forum.xda-developers.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://forum.xda-developers.com/galaxy-note-8/help/unbrick-methods-t3703767
https://forum.xda-developers.com/galaxy-note-8/help/to-fix-efs-secondary-note-8-t3785600
https://forum.xda-developers.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
Click to expand...
Click to collapse
thanx! for your guide but i have this problem after taking an official OTA!
DM-Verity ERRor!
any help will be greatly appreciated!

---

Can someone explain me what is this EFS ?? I'm flashing roms many many times and I hadn't such problems etc

---

klisza1993 said:
Can someone explain me what is this EFS ?? I'm flashing roms many many times and I hadn't such problems etc
Click to expand...
Click to collapse
Just Google "EFS android"

---

pixel989 said:
thanx! for your guide but i have this problem after taking an official OTA!
DM-Verity ERRor!
any help will be greatly appreciated!
Click to expand...
Click to collapse
Follow
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)
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
Click to expand...
Click to collapse
Note -
dm verify cannot be completely fixed, it can only be bypassed (in the system by flashing no dm verify).
You will need to wait for 7 days for oem unlock (there is no method to skip oem unlock)
Warranty will be voided (KNOX 1) - don't think there is a method to avoid tripping knox.
Suggest installing a custom rom after oem unlock (many reports that no dm verify on latest oreo does not work without root)

---

klisza1993 said:
Can someone explain me what is this EFS ?? I'm flashing roms many many times and I hadn't such problems etc
Click to expand...
Click to collapse
EFS partition is not touched when flashing roms (they actually do but in a safe way), only retards like I would try to mod efs partition.

---

Hi guys, will it work in my case? https://ibb.co/mJRcHK
Device is SM-N950N FRP ON and OEM ON.
What kind of solution should I follow?

---

@Anvar2005 - This looks like a drk verify error. Which binary are you on? frp bypass only works with binary 3. You will not find anything for frp unlock on this forum. Same steps for drk verify but use nougat.