Factory reset on merged storage - Shall I lose my data As we know, merged storage (that is, an internal SD card partition emulated by FUSE in the data partition (/data/media/0 &rarr; /storage/emulated/0) is a common thing to be found on recent devices running Kitkat and higher. Now, since this is my internal storage and contains all app and non-app data, will doing a factory reset be true to its name and wipe all of /cache and /data, including /data/media? Or, will it be considerate and keep the things under /data/media?

Note: I am asking this question to clarify a doubt and because I am not willing to do a factory reset to check this on my Nexus 9, which is the only device I have which has merged storage; but note that I asked this question for all devices with merged storage in general, which implies most stock devices with stock Android recovery on Android 4.4 and up. Please do not take the question just in context of Nexus devices. To prevent the question from being considered too broad, here are the constraints:


The device must have a standard processor (Snapdragon)
It must be AOSP stock. No OEM customized ROMs (Touchwiz, ZenUI, ColorOS) needs to be considered.
Devices are not rooted and have stock AOSP recovery.
AOSP version can be considered for 4.4.4 and 5.0 to 5.1 .
It must have merged storage.


(An answer relating to Motorola Moto devices and the Nexus 5 &amp; 9 will be enough)

P.S. : I know that TWRP preserves /data/media while doing a wipe of /data and /cache, but I am referring here only to the stock recovery's behaviour in case of a factory reset.
According to the article  Reset your Nexus device to factory settings (Nexus 5 and Nexus 9 listed too) by Google,


  By performing a factory data reset, all data will be erased from the device. While any data stored in your Google Account will be restored, all apps and their associated data will be uninstalled. Make sure you back up your data before you do a factory data reset.


The testimony of a Nexus 4 owner, coupled with supporting arguments from other Reddit users confirms that factory data reset will nuke everything. 

As per AndroidPIT on How to factory reset the Nexus 5 for better performance


  Since the release of Android 4.4, the ‘factory data reset’ option (accessible in the settings menu) performs the same job as a ‘hard’ reset. All of your user files, apps, etc will be deleted and your device will revert to a factory fresh state.


Their hard reset is not our hard-reset but our factory-reset using recovery mode.

Guide To Perform Hard Reset Android HTC Nexus 9 on guidebelajar blog (has useful screenshots) confirms that factory data reset for Nexus 9 would also remove every user file created or moved into the device.



As per the article How do I reset my phone? by Motorola


if you decide to factory data reset using Settings app, you would be given a choice to erase media (files under /data/media/ such as music, videos, pictures),
should you decide to boot into recovery mode, everything would be deleted


The information is also valid for Moto G (1st Gen, 2nd Gen, 3rd Gen) family of devices.

(That's all for now)