what does 'factory reset' do?

[Mike Lang1]

Hi all,
I have searched but couldn't find any info.

1) what exactly happened when we do 'factory reset'? What gets restored?

In other words, if I removed/deleted some bloatware from /system/apps on a rooted phone and if I do a 'factory reset',
will those come back just as the phone was brand new? Where is this 'backup' stored?

2) Instead of installing a custom recovery and do a NANDROID backup, will it be the same if I do a bunch
of 'dd' commands directly from the partitions? Something like the following for a Note 2?

dd if=/dev/block/mmcblk0p3 of=/storage/extSdCard/efs.img bs=4096 (backup /efs)

dd if=/dev/block/mmcblk0p13 of=/storage/extSdCard/system.img bs=4096 (backup /system)

...etc..
Thank you.
mike

 

[Paul627g]

1) what exactly happened when we do 'factory reset'? What gets restored?

When you preform a factory reset it erases your /data, /cache & /dalvik cache. Anything you haven't sync'd or backed up like your contacts, text messages, various settings, etc will be lost. However as long as you have them sync'd to your Gmail account all will be okay. Always make sure you have your device set to backup to Google under Backup and Restore in Settings. This will keep track of your apps and some settings.

Best way to avoid trouble is use an application like Helium which DOESN'T require root access to make backups of your apps & data. SMS Backup & Restore can handle SMS messages, again no root required.

In other words, if I removed/deleted some bloatware from /system/apps on a rooted phone and if I do a 'factory reset',
will those come back just as the phone was brand new? Where is this 'backup' stored?

If you removed bloatware from /system/apps on a rooted device a factory reset is BAD. NEVER USE THE FACTORY RESET IN SETTINGS ON A ROOTED DEVICE. If your going to do a factory reset from a rooted device, then use the option in your custom recovery. Second, no it won't restore any removed bloat, etc. That is your problem to handle with a backup of the apps or making a Nandroid full system backup. Backups from Titanium, MyBackup, Helium, ClockWorkMod & TWRP are normally kept within a folder on your sdcard/internal storage. If your running Android 4.2 and higher some backups like TWRP can be found in the root level of your device under /data/media/TWRP

2) Instead of installing a custom recovery and do a NANDROID backup, will it be the same if I do a bunch
of 'dd' commands directly from the partitions? Something like the following for a Note 2?

dd if=/dev/block/mmcblk0p3 of=/storage/extSdCard/efs.img bs=4096 (backup /efs)

dd if=/dev/block/mmcblk0p13 of=/storage/extSdCard/system.img bs=4096 (backup /system)

Yes you can do this to do a backup of these locations but honestly its just as easy if not better to just use your custom recovery's backup option instead. It will make a full backup image of your devices important areas to restore in the event of something going wrong or simply wanting to revert to your backup.

Hope this helps !

Paul
Forums Moderator

 

[Mike Lang1]

Thank you Paul, I appreciate your reply.

- I understand the user apps/data parts.

- why did you say "we should never do factory reset on a rooted phone"?

- from what you said, factory reset **will not** restore the phone to a factory state. I thought there is another copy of system
stored somewhere on the phone that it will be used to restore to its factory state.

Thanks again.
mike

 

[Mike Lang1]

The reason I asked the 'dd' command is that my Note 2 was rooted but I did not install a custom recovery. I use CF Autoroot and it keeps the stock recovery.
I try not to install CWM or TWRP if I don't need it (more things to go wrong )

 

[Paul627g]

Reason we don't attempt a factory reset from within the Android OS itself is many people have ended with bricks from this.
It's just been rule of thumb if your rooted then use the custom recovery to do a factory reset.




Sent from my HTC ONE using AC Forums mobile app

 

[Mike Lang1]

Reason we don't attempt a factory reset from within the Android OS itself is many people have ended with bricks from this.
It's just been rule of thumb if your rooted then use the custom recovery to do a factory reset.

But rooted != custom recovery


Thanks for the advise.




Sent from my HTC ONE using AC Forums mobile app

 

[Mike Lang1]

Any preference on CWM vs TRWP?

 

[Paul627g]

My preference is TWRP. Why?

Back about two years ago when TWRP hit the scene I really liked what they offered over CWM, I switched and just never looked back.




Sent from my HTC ONE using AC Forums mobile app

 

[Mike Lang1]

thanks. I'm trying to decide which one I should install to my Note 2. I'm rooted with a stock recovery.