[Galaxy Grand Duos i9082 Q&A, Help & Troubleshootin] Gautam Gundap:
Yes you can. This method is only for the android smartphones where the recovery does not support sd-ext/sdext2 backup, format and restore. If your device has an official or unofficial recovery on xda forum that supports sdext2/sd-ext then it can be done directly from the recovery menu options and this method is not required. If not follow the below steps

1. Find a recovery on the web/xda for your specific device that supports any file manager directly through recovery which has an option for terminal/bash command inputs and execution. Even if the recovery does not have a file manager support but has the terminal/bash command facility then that will do. Philz touch/non touch recovery for your specific device should support this. It has aroma file manager with terminal/bash commands support. I hope you know how to install a recovery img/partition on your device

2. Depending upon which app you are using for sdext2/sd-ext partition to handle, you will find a file under init.d directory for mounting this partition. This file contains script commands for mounting this partition. You need to edit this file and find the script command. For example if you are using link2sd on galaxy grand then the script command is mount -t ext4(your partition type) -o rw(permissions set) /dev/block/vold/179.10(this is the allocated partition address for your sdext2/sd-ext partition specific to your device and will be different for different devices) /data/sdext2.

3. If you want to do a full backup then reboot into recovery go to file manager and command prompt and type the mount script for sdext2/sd-ext and press enter.

4. Exit file manager/terminal and from recovery select full backup( boot, recovery, system, data ). This will backup your full device. You can backup .android_secure, data/media and extsdcard depending on your choice but mind it the backup file size will be large and you should have enough space on your extsdcard for it. If .android_secure is empty/not used you need not backup this ( if you don't have apps on extsdcard this will be empty) .

While performing the backup your recovery will display sd-ext partition not found. Could not backup sd-ext. Don't panic when you see this and just ignore it. Your sdext2/sd-ext partition will be backed up.

5. To format and then restore, boot into recovery and go to file manager/terminal and execute the above mount script and go back to recovery. Then format all above mentioned partitions that you have backed up and reboot from recovery back into recovery. You will be prompted for keep/apply root 1. Yes 2. No. Select yes.

6. Once you have rebooted back into recovery, again go to file manager/terminal and execute the above mount script and go back to recovery.

7. Now select full restore and select your backed up file and your device will be restored to exact state at the time you created your backup.

Note: You can also do customized/selected partitions backup and this also applies for format and restore too through philz cwm touch recovery.

I hope I have made this as simple as possible to understand and implement the procedure. If you have any doubts/queries you can get back.