If you are a hard core Android user who loves flashing ROMs and tinkering with your device to limits, all this can be a fun experience, but as you probably already know it does not come without some possible risks if you are not careful. Having a bad EFS folder can be your worst nightmare yet which cost many Android users sleepless nights. Troubleshooting EFS related problems like
E: failed to mount /efs could prove to be an uphill task, more so like reviving a hard bricked device. A damaged EFS folder will cause your device to lose any kind of mobile networking capabilities leaving you unable to receive any calls, messages or access the internet. In Samsung devices, the EFS partition also the EFS folder houses critical information about your device core networking data: IMEI, WIFI, Bluetooth, MAC’s, radio info and others.
Most devices with a bad EFS folder/EFS partition will show “Blank IMEI” “Null Null” “Not registered on network” and probably Unknown Baseband version as well. A device IMEI is the unique ID assigned to every GSM phone and which can be used to validate a phone to the cellular network among other purposes. Without the proper IMEI data information, your device network tasks will not function.
How to Fix E: failed to mount /efs (invalid argument) in All Samsung Galaxy Phones
I recently had a Galaxy S2 i9100 for repair with blank IMEI number and No baseband version and no network at all. With no previous backup of the EFS folder or a backup of the IMEI, I graced myself for the task ahead.
The most recommended programs; EFS Professional and EFS backup/restore tool could not repair the corrupt EFS partition or restore correct IMEI data successfully.
Strange enough, while trying to flash stock ROM in ODIN, the device got stuck at the Samsung boot logo and could not boot all the way up, kept restarting. Then, I encountered this error in stock recovery.
E: failed to mount /efs (invalid argument) factory resetting and clearing cache did not help either to solve the boot loop problem.
I tried upgrading the device from Ginger bread to official Jellybean 4.1.2 ROM in hope that a complete wipe would enhance the chances of solving the infinite boot loop and also repair EFS folder data which would get the network working again. I tried different Odin flashable Jelly Bean ROMS but after Odin finished with no errors, the device still could not boot past the Samsung boot logo, kept restarting frequently. Soon, I realized that no ROM flash, kernels flash or CWM jigs could resolve the error. I had to repair the damaged EFS mount point first.
I scoured on the internet but information about fixing this error was scanty and I could not find a working solution to fix Galaxy S2 EFS failed to mount.
At last, I stumbled upon some information about ” failed to mount partition” errors for another device. So I did my diligent research on getting the same to work on my Galaxy S2 and possibly every other Samsung Galaxy device out there with E: failed to mount /efs problem.
So today am posting this solution in the hope to save many others the agony of getting stuck with a seemingly useless device.
NOTE: This solution has worked on GS2 i9100, Galaxy Note 3, and Galaxy tab 3. If you are having the same problem with another Samsung Galaxy device, this same tutorial will could work but you MUST change the EFS mount point I.e ‘mmcblk0p…’ part to match your specific phone or tablet EFS mount point number. For instant, Galaxy S2 i9100 EFS mount point is mmcblk0p1, for Galaxy S3 i9300 use mmcblk0p3 , Galaxy Note 3 use mmcblk0p3 as well and so on depending on your particular device partition table. So look around for the correct EFS mount point for your Galaxy device.
How to repair EFS partition mount errors on Samsung Galaxy Phones
- Go to Sammobile or Samsung-updates website and download an official stock firmware for your phone and flash it in Odin. For Galaxy S2, I flashed the i9100VJMS1 4.1.2 Jelly bean.
- Next you need to flash a custom recovery like CWM recovery and also root your device either in recovery or ODIN. For GSII, I used PhilZ CWM.zip recovery which is root ready for your installed firmware. (No need to root ROM separately)
- Install ADB on your computer. See How to Install ADB, Fast boot drivers the easier way.
- Now power on your device into recovery mode ( Press Power Key+Volume up+Home simultaneously)
- Once in recovery, connect your device to the PC via USB cable.
- In CWM recovery select “mount and storage > mount /system” (If it indicates “unmount/system” then leave it as that)
- On the PC, Open ADB command window and type:
mount -w -t ext4 /dev/block/mmcblk0p1
NOTE: If you get this error: can’t find /dev/block/mmcblk0px in /etc/fstab just ignore, reboot device and cross your fingers that it works. After you run the above ADB commands your device should reboot all the way up and Voila! You should be back up and running again.
If you find that your Power key, Menu and lock screen are not working after this, you are probably stuck in factory mode like I was in this case. To fix a device stuck in factory mode, use the latest version EFS Professional.
TIP: If you are not sure which particular mmcblk0p* EFS mount point to use, find it through ADB. After mounting /system in step 6 above, connect device to PC, Open ADB and type:
adb shell (try
cat/proc/mount if mount does not work)
A list of the device partitions will be listed. Find which one is the EFS mount point.
DISCLAIMER: This is a technical repair tutorial, Self Tech Genius is NOT Liable for any bricked devices as a result!
IMPORTANT: Repairing EFS mount point error also restored EFS partition data and fixed the Blank IMEI and Unknown Baseband problem on both Galaxy S2 and Samsung Galaxy Note 3. I was hence able to access the network again which was just epic! I can only hope it will also be of great help to many others with the same E: failed to mount /efs (invalid argument) problem.
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