18 Aug: EFS auto backup script (for devs)

---

I have now seen a number of cases of the EFS partition getting wiped / corrupted on the SGS II, leaving users with an effectively useless phone.

With this in mind, i've written a little init.d script for my ROM which backs up the EFS partition on boot if a backup does not already exist. A non intrusive safety net for users if you will.

The script just needs a suitable boot image that runs init.d, although it could easily be tacked onto the end of install-recovery.sh if that's not the case.

I'd love to encourage all developers to use this script for users' sake!

You can download the script here - http://cl.ly/2j0p0R3F07052m2T2u0e - but it's very simple, here's the code...

#!/system/bin/sh
# EFS auto backup script for Samsung Galaxy S II
# By @paulobrien - http://s2.MoDaCo.com

mount /dev/block/mmcblk0p11 /sdcard

if [ ! -f /sdcard/efs.autobackup.img ];
then
        dd if=/dev/block/mmcblk0p1 of=/sdcard/efs.autobackup.img
fi

umount /sdcard

Note the manual mount / umount of sdcard is necessary because this happens late in the boot process.

Cheers!

P

Hats of to you Paul.Although I have already made a backup of my EFS folder,such a script would save MANY people from A LOT of trouble.

Originally Posted by tolis626

Hats of to you Paul.Although I have already made a backup of my EFS folder,such a script would save MANY people from A LOT of trouble.

i havent...never did. i think i wiped about a hundred times now and flashed and reflashed...is it possible to recover the efs folder?

Originally Posted by haasgo

i havent...never did. i think i wiped about a hundred times now and flashed and reflashed...is it possible to recover the efs folder?

If your phone is working, it means your EFS partition is still there...

You can back it up using the many tutorials out there in the forum...

Sent from my GT-I9100 using XDA Premium App

Problem is that the users who read how to backup EFS folder fall in to two category s those that read up first and would have backed up EFS and those that only pick the manual up after something is broke .
This script would be a saver for many of the second group and big thanks to Paul and i hope devs do run with it .

jje

I would like to adapt your script for Nexus S.

Once i got the img file of efs partition, how do can a make a script for restoring thet img file to efs partition?

Or what to do with that img file?

EDIT: @ paul - One more question - how do I mount /sdcard on Nexus S through the script? mount command in the Terminal Emulator shows my /dev/blocks/vold/179:3 as mount point, but if I use that mount point in the script it won't mount the /sdcard. Any idea?

EDIT2: I got it working with this command:

mount /dev/block/platform/s3c-sdhci.0/by-name/media /sdcard

and I got the efs.autobackup.img on my sdcard.

How do I restore the efs.autobackup.img to efs partition?

Thanks Paul this is a very useful utility hope it gets sticky

May i ask what conditions these people are falling foul of getting the EFS wiped? Is it rouge roms/cwm zips, wiping to much in recovery, Odin flashing?

Curious so i may steer clear, have a backup but staying away is half the battle

Originally Posted by paulobrien

You can download the script here - http://cl.ly/2j0p0R3F07052m2T2u0e - but it's very simple, here's the code...

#!/system/bin/sh
# EFS auto backup script for Samsung Galaxy S II
# By @paulobrien - http://s2.MoDaCo.com

mount /dev/block/mmcblk0p11 /sdcard

if [ ! -f /sdcard/efs.autobackup.img ];
then
        dd if=/dev/block/mmcblk0p1 of=/sdcard/efs.autobackup.img
fi

umount /sdcard

Hi Paul, I have modified your script so that it makes a tar file, tar file keeps the permissions for the efs partition and its easier to restore. Here it is:

#!/system/bin/sh
# EFS auto backup script for Samsung Galaxy S II
# By @paulobrien - http://s2.MoDaCo.com

mount /dev/block/mmcblk0p11 /sdcard

if [ ! -f /sdcard/efs_autobackup/efs-backup.tar.gz ];
then
  mkdir /mnt/sdcard/efs_autobackup
  busybox tar zcvf /sdcard/efs_autobackup/efs-backup.tar.gz /efs
fi

umount /sdcard

Originally Posted by mynamesteve

Thanks Paul this is a very useful utility hope it gets sticky

May i ask what conditions these people are falling foul of getting the EFS wiped? Is it rouge roms/cwm zips, wiping to much in recovery, Odin flashing?

Curious so i may steer clear, have a backup but staying away is half the battle

Some hit "wipe EFS" in ODIN.

It's possible to mess up a zip badly enough to wipe EFS

A normal wipe shouldn't do it, but a bad CWM build could in theory do it...

A dodgy "virus" could do it, if it were targetting rooted phones, or had a root exploit.

That's why I keep an EFS backup on my PC and off-site

Originally Posted by brainmaster

Hi Paul, I have modified your script so that it makes a tar file, tar file keeps the permissions for the efs partition and its easier to restore.

Nope dd is much better, but safer to have both, but dd should be used with bs=4096k option.