How to fix - E:failed to mount /efs (Invalid argument)

[anukilimanoor]

My phone was dead due to unknown reason. It was very slow for last couple of days, so I reboot the phone into recovery and then wipe cache and dalvik. After the wipe I reboot the phone but it stuck on Samsung logo. So I tried different unsuccessful methods like, flash stock ROM, restore efs folder, etc...

After flashing the stock ROM, rebooted the phone into recovery for factory reset, then only I noticed the error E:failed to mount /efs (Invalid argument). If you are on CWM recovery then you may not see this error.

Solution:
Flash an official firmware from sammobile
Flash CWM recovery
Boot into Recovery
Select mount and storage -> mont /system
Connect your phone to PC using USB cable
Open ADB command window and type the following commands

adb shell

mke2fs /dev/block/mmcblk0p3

mount -w -t ext4 /dev/block/mmcblk0p3

reboot

Now your phone will boot, but it may be in factory mode (ie you can see yellow box showing some ROM information).

Remove factory mode:
There are different methods that we can use to remove factory mode
In my case
1. Installed custom ROM to get root access
2. Instaled kTool
3. Copy the backup of my efs into sdcard (you can use .img or tar file)
4. Open kTool and restore the efs
5. Reboot the phone

* This method is the easiest and safest method because when you are getting the efs mount error there is a chance of loosing your IMEI and some other files, in that situation the following methods will not work.

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install ES File Explorer
3. Open ES File Explorer and turn on Root Explorer
4. Navigate to /efs folder
5. Open factorymode as txt in ES Note Editor
6. Change it from OFF to ON and save
7. Reboot your phone

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install Terminal Emulator
3. Run the following commands

su
rm /efs/FactoryApp/keystr
rm /efs/FactoryApp/factorymode
echo -n ON >> /efs/FactoryApp/keystr
echo -n ON >> /efs/FactoryApp/factorymode
chown 1000.1000 /efs/FactoryApp/keystr
chown 1000.1000 /efs/FactoryApp/factorymode
chmod 0744 /efs/FactoryApp/keystr
chmod 0744 /efs/FactoryApp/factorymode
reboot

 

[w9999]

I can't find factorymode in efs folder.

Sent from my GT-I9300

 

[ArkThompson]

Restoring this kind of backup http://xdaforums.com/galaxy-s3/development-i9305/warning-guide-backup-restore-imei-nv-t1946915 will also remove factory mode (at least it did when I softbricked my i9305 and had to recover efs).

 

[cruising6n]

My phone was dead due to unknown reason. It was very slow for last couple of days, so I reboot the phone into recovery and then wipe cache and dalvik. After the wipe I reboot the phone but it stuck on Samsung logo. So I tried different unsuccessful methods like, flash stock ROM, restore efs folder, etc...

After flashing the stock ROM, rebooted the phone into recovery for factory reset, then only I noticed the error E:failed to mount /efs (Invalid argument). If you are on CWM recovery then you may not see this error.

Solution:
Flash an official firmware from sammobile
Flash CWM recovery
Boot into Recovery
Select mount and storage -> mont /system
Connect your phone to PC using USB cable
Open ADB command window and type the following commands

adb shell

mke2fs /dev/block/mmcblk0p3

mount -w -t ext4 /dev/block/mmcblk0p3

reboot

Now your phone will boot, but it may be in factory mode (ie you can see yellow box showing some ROM information).

Remove factory mode:
There are different methods that we can use to remove factory mode
In my case
1. Installed custom ROM to get root access
2. Instaled kTool
3. Copy the backup of my efs into sdcard (you can use .img or tar file)
4. Open kTool and restore the efs
5. Reboot the phone

* This method is the easiest and safest method because when you are getting the efs mount error there is a chance of loosing your IMEI and some other files, in that situation the following methods will not work.

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install ES File Explorer
3. Open ES File Explorer and turn on Root Explorer
4. Navigate to /efs folder
5. Open factorymode as txt in ES Note Editor
6. Change it from OFF to ON and save
7. Reboot your phone

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install Terminal Emulator
3. Run the following commands

su
rm /efs/FactoryApp/keystr
rm /efs/FactoryApp/factorymode
echo -n ON >> /efs/FactoryApp/keystr
echo -n ON >> /efs/FactoryApp/factorymode
chown 1000.1000 /efs/FactoryApp/keystr
chown 1000.1000 /efs/FactoryApp/factorymode
chmod 0744 /efs/FactoryApp/keystr
chmod 0744 /efs/FactoryApp/factorymode
reboot

Hi,

my GT-I9300 is stucked at Samsung Boot Logo. When I start the phone in recovery mode it shows e:failed to mount /efs (Invalid argument).
I have no efs or any other backup....
Tried to flash stock rom with odin but it doesnt work.....

Does your soloution work in my case?
Do you have any other soloutions for me? I´m reading XDA threads since hours....

 

[anukilimanoor]

I can't find factorymode in efs folder.

Sent from my GT-I9300

Are you able to boot the phone?

Hi,

my GT-I9300 is stucked at Samsung Boot Logo. When I start the phone in recovery mode it shows e:failed to mount /efs (Invalid argument).
I have no efs or any other backup....
Tried to flash stock rom with odin but it doesnt work.....

Does your soloution work in my case?
Do you have any other soloutions for me? I´m reading XDA threads since hours....

Try the other option and see the imei. If it is ok then no need to restore it.

 

[w9999]

---------- Post added at 09:47 PM ---------- Previous post was at 09:45 PM ----------

Are you able to boot the phone?



Try the other option and see the imei. If it is ok then no need to restore it.

i restore efs folder.now everything is ok.

 

[cruising6n]

Which other option? :angel:

 

[ndmuni]

Fixed -cannot mount efs

Thanks OP, I just recovered my S3 moments ago, followed yr instructions to the T,
My original imei intact, albeit booted to safe mode, just turn to ON in root explorer and all system back to normal. Thanks again

EDIT: Just for info I install philz_touch_4.00-b21-i9305-fixed_Ported_By_ausdim.tar.md
and i did not mount system.

 

[nachocarp]

My phone was dead due to unknown reason. It was very slow for last couple of days, so I reboot the phone into recovery and then wipe cache and dalvik. After the wipe I reboot the phone but it stuck on Samsung logo. So I tried different unsuccessful methods like, flash stock ROM, restore efs folder, etc...

After flashing the stock ROM, rebooted the phone into recovery for factory reset, then only I noticed the error E:failed to mount /efs (Invalid argument). If you are on CWM recovery then you may not see this error.

Solution:
Flash an official firmware from sammobile
Flash CWM recovery
Boot into Recovery
Select mount and storage -> mont /system
Connect your phone to PC using USB cable
Open ADB command window and type the following commands

adb shell

mke2fs /dev/block/mmcblk0p3

mount -w -t ext4 /dev/block/mmcblk0p3

reboot

Now your phone will boot, but it may be in factory mode (ie you can see yellow box showing some ROM information).

Remove factory mode:
There are different methods that we can use to remove factory mode
In my case
1. Installed custom ROM to get root access
2. Instaled kTool
3. Copy the backup of my efs into sdcard (you can use .img or tar file)
4. Open kTool and restore the efs
5. Reboot the phone

* This method is the easiest and safest method because when you are getting the efs mount error there is a chance of loosing your IMEI and some other files, in that situation the following methods will not work.

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install ES File Explorer
3. Open ES File Explorer and turn on Root Explorer
4. Navigate to /efs folder
5. Open factorymode as txt in ES Note Editor
6. Change it from OFF to ON and save
7. Reboot your phone

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install Terminal Emulator
3. Run the following commands

su
rm /efs/FactoryApp/keystr
rm /efs/FactoryApp/factorymode
echo -n ON >> /efs/FactoryApp/keystr
echo -n ON >> /efs/FactoryApp/factorymode
chown 1000.1000 /efs/FactoryApp/keystr
chown 1000.1000 /efs/FactoryApp/factorymode
chmod 0744 /efs/FactoryApp/keystr
chmod 0744 /efs/FactoryApp/factorymode
reboot

i did it but i have this issue when inputing "mount -w -t ext4 /dev/block/mmcblk0p3"
It says "mount: can´t find /dev/block/mmcblk0p3 in /etc/fstab"

Please, save my day.

 

[anukilimanoor]

i did it but i have this issue when inputing "mount -w -t ext4 /dev/block/mmcblk0p3"
It says "mount: can´t find /dev/block/mmcblk0p3 in /etc/fstab"

Please, save my day.

Is there any error while running this command
mke2fs /dev/block/mmcblk0p3

 

[nachocarp]

Is there any error while running this command
mke2fs /dev/block/mmcblk0p3

No, its all fine.

 

[ahmmyreal]

i did it but i have this issue when inputing "mount -w -t ext4 /dev/block/mmcblk0p3"
It says "mount: can´t find /dev/block/mmcblk0p3 in /etc/fstab"

Please, save my day.

same with me too, pls save my day

Edit: so in the command window, last line of code after running

mke2fs /dev/block/mmcblk0p3

i got :

The filesystem will be automatically checked every 35 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.

So in the code:

mount -w -t ext4 /dev/block/mmcblk0p3

I replaced -w and -t with -c and -i respectively.

Note: -c and -i was pulled from:

The filesystem will be automatically checked every 35 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.

reboot

Boom! it worked.
DONT FOEGET TO HIT THE THANKS BUTTON

 

[nachocarp]

same with me too, pls save my day

Edit: so in the command window, last line of code after running

mke2fs /dev/block/mmcblk0p3

i got :

The filesystem will be automatically checked every 35 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.

So in the code:

mount -w -t ext4 /dev/block/mmcblk0p3

I replaced -w and -t with -c and -i respectively.

Note: -c and -i was pulled from:

The filesystem will be automatically checked every 35 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.

reboot

Boom! it worked.
DONT FOEGET TO HIT THE THANKS BUTTON

I did it and this is what it shows. Then when i try to remove factory mode, i have trouble when inputing

chown 1000.1000 /efs/FactoryApp/keystr
and
chmod 0744 /efs/FactoryApp/keystr

Still, it worked but i dont have my imei.

When you reboot from adb, does the phone starts with the correct imei?
Do i need to have a previous backup for this method to work?

 

[nachocarp]

Is there any error while running this command
mke2fs /dev/block/mmcblk0p3

When you reboot from adb, does the phone starts with the correct imei?
Do i need to have a previous backup for this method to work?

 

[andrewwright]

Nice tut mate. Nice and detailed. :thumbup: great info for the community.

 

[risvegliare]

My phone was dead due to unknown reason. It was very slow for last couple of days, so I reboot the phone into recovery and then wipe cache and dalvik. After the wipe I reboot the phone but it stuck on Samsung logo. So I tried different unsuccessful methods like, flash stock ROM, restore efs folder, etc...

After flashing the stock ROM, rebooted the phone into recovery for factory reset, then only I noticed the error E:failed to mount /efs (Invalid argument). If you are on CWM recovery then you may not see this error.

Solution:
Flash an official firmware from sammobile
Flash CWM recovery
Boot into Recovery
Select mount and storage -> mont /system
Connect your phone to PC using USB cable
Open ADB command window and type the following commands

adb shell

mke2fs /dev/block/mmcblk0p3

mount -w -t ext4 /dev/block/mmcblk0p3

reboot

Now your phone will boot, but it may be in factory mode (ie you can see yellow box showing some ROM information).

Remove factory mode:
There are different methods that we can use to remove factory mode
In my case
1. Installed custom ROM to get root access
2. Instaled kTool
3. Copy the backup of my efs into sdcard (you can use .img or tar file)
4. Open kTool and restore the efs
5. Reboot the phone

* This method is the easiest and safest method because when you are getting the efs mount error there is a chance of loosing your IMEI and some other files, in that situation the following methods will not work.

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install ES File Explorer
3. Open ES File Explorer and turn on Root Explorer
4. Navigate to /efs folder
5. Open factorymode as txt in ES Note Editor
6. Change it from OFF to ON and save
7. Reboot your phone

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install Terminal Emulator
3. Run the following commands

su
rm /efs/FactoryApp/keystr
rm /efs/FactoryApp/factorymode
echo -n ON >> /efs/FactoryApp/keystr
echo -n ON >> /efs/FactoryApp/factorymode
chown 1000.1000 /efs/FactoryApp/keystr
chown 1000.1000 /efs/FactoryApp/factorymode
chmod 0744 /efs/FactoryApp/keystr
chmod 0744 /efs/FactoryApp/factorymode
reboot

I've got a couple of questions
1. On what official firmwares should i choose from sammobile? because there's a lot firmware from different region
2. I've install adb before, but in the command prompt, it said that adb is not recognized. What should i do?

 

[mihafiz]

path

>>2. I've install adb before, but in the command prompt, it said that adb is not recognized. What should i do?
The path to adb.exe may not have been properly set in the environment variable PATH.
You may just 'cd' to the folder named "platform-tools" and run adb.exe . It should work as it's meant to.

 

[awilmets]

help for samsung Galaxy S3- I9300

My phone was dead due to unknown reason. It was very slow for last couple of days, so I reboot the phone into recovery and then wipe cache and dalvik. After the wipe I reboot the phone but it stuck on Samsung logo. So I tried different unsuccessful methods like, flash stock ROM, restore efs folder, etc...

After flashing the stock ROM, rebooted the phone into recovery for factory reset, then only I noticed the error E:failed to mount /efs (Invalid argument). If you are on CWM recovery then you may not see this error.

Solution:
Flash an official firmware from sammobile
Flash CWM recovery
Boot into Recovery
Select mount and storage -> mont /system
Connect your phone to PC using USB cable
Open ADB command window and type the following commands

adb shell

mke2fs /dev/block/mmcblk0p3

mount -w -t ext4 /dev/block/mmcblk0p3

reboot

Now your phone will boot, but it may be in factory mode (ie you can see yellow box showing some ROM information).

Remove factory mode:
There are different methods that we can use to remove factory mode
In my case
1. Installed custom ROM to get root access
2. Instaled kTool
3. Copy the backup of my efs into sdcard (you can use .img or tar file)
4. Open kTool and restore the efs
5. Reboot the phone

* This method is the easiest and safest method because when you are getting the efs mount error there is a chance of loosing your IMEI and some other files, in that situation the following methods will not work.

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install ES File Explorer
3. Open ES File Explorer and turn on Root Explorer
4. Navigate to /efs folder
5. Open factorymode as txt in ES Note Editor
6. Change it from OFF to ON and save
7. Reboot your phone

OR

1. Root your phone (Either root manually or install a custom ROM)
2. Install Terminal Emulator
3. Run the following commands

su
rm /efs/FactoryApp/keystr
rm /efs/FactoryApp/factorymode
echo -n ON >> /efs/FactoryApp/keystr
echo -n ON >> /efs/FactoryApp/factorymode
chown 1000.1000 /efs/FactoryApp/keystr
chown 1000.1000 /efs/FactoryApp/factorymode
chmod 0744 /efs/FactoryApp/keystr
chmod 0744 /efs/FactoryApp/factorymode
reboot

My S3-I9300 not detect in Adb. "error: device not found"

 

[mihafiz]

tool to move about factory and user mode

I've used the following tool to go 'to and fro' the factory mode. It's useful enough.
[TOOL] Updated! 26/06/14 - EFS Professional … | Samsung Galaxy S II I9100 | XDA Forums
http://xdaforums.com/galaxy-s2/orig-development/tool-updated-09-06-14-efs-professional-t1308546

 

[waldezca]

Same trouble and fix it!

At this step:

Code:
mount -w -t ext4 /dev/block/mmcblk0p3

at the end of the sentence put an space slash and efs, you have to see something like this:

Code:
mount -w -t ext4 /dev/block/mmcblk0p3 / efs --> (then push enter key, then make the last step "reboot" to reboot your phone).

Then your phone have to start normaly but in recovery mode [showing you a yellow information of the system phone]. Look at this thread http://xdaforums.com/showthread.php?t=2389426