Develop Bugs

Factory wipe questions

I've had my nexus since December and have tried several ROMs since then--not a total noob, but there's a lot I don't know.
I've been wondering what part of the memory is left untouched by the factory wipes that I've been doing in preparation to flash a ROM? And is there any need to periodically wipe that portion of the memory to remove any remnants of ROMs or deleted apps or anything else that is potentially problem causing or just eating up memory space?
And would your answer explain this: I once did a factory wipe and then accidentally selected reboot before flashing the new ROM and the phone booted normally into the ROM I thought I had just wiped.

factory wipe (data/cache) in CWM only removes the apps, user data, and cache
it leaves /data/media alone (this is the /sdcard/ partition)
so if you hit reboot after a factory reset, it will still keep the same rom as /system is untouched unless you remove it or the rom installer script for the new rom deletes the partition.

When you wipe you clean the ROM for a new one to come. and as far as I know there's no storage to be cleaned up. When yo wipe cache and data it should be good to go.
Sent from my Galaxy Nexus using xda app-developers app

if you factory wipe using CWM, it will keep the data/media folder, which is all your sdcard contents. other than that the rest of the data folder (apps/settings) will get wiped.
if you wipe userdata using fastboot, either by typing in 'fastboot erase userdata' or when using the -w command when installing factory images then your sdcard will get formatted too.

Anytime you want to change Rom's just move the important files/pics/etc to a subfolder of /data/media or just copy them to your PC first. I think its good to factory reset every once in a while to clear out the remnants of uninstalled programs. Seems to speed up the phone too in my opinion.

Mounts & Storage → Format System "Not SD"
It will help with issues people mostly run into.
bOx Stash - https://www.box.com/shared/d8a46b7252c38069deb1

completely wipe the phone?

Just wondering, as i'm probably selling my Galaxy S3 soon... what's the easiest way to completely wipe everything off the phone? Pictures, apps, documents.... everything? Will re-install a custom ROM after wiping.... just want to make sure all personal data is off the phone.

elementaldragon said:
Just wondering, as i'm probably selling my Galaxy S3 soon... what's the easiest way to completely wipe everything off the phone? Pictures, apps, documents.... everything? Will re-install a custom ROM after wiping.... just want to make sure all personal data is off the phone.
Click to expand...
Click to collapse
I imagine using twrp would be the best way. Not sure if there is another alternative. Maybe odin.
First before wiping system you may want to wipe internal storage (after backing up your internal storage to your computer or something first of course). Then boot up your current system and transfer a rom you want to install to your internal storage. Then reboot to twrp and wipe system, factory reset, cache and dalvik. Then install a rom fresh and then it should be ready to go. This is what I do after selling a device, before shipping to a customer.

.... wouldn't copying a custom ROM to the internal storage BEFORE wiping System and everything also erase the custom ROM i just transferred to the device?
And i mean wiping EVERYTHING. basically as if the phone was just taken out of the box, and unlocked, rooted, and custom ROM installed. No left over files whatsoever. Don't think wiping just System does that, does it? Wouldn't i do the "Wipe Internal Storage" or something like that? Think that's about what i did on my Motorola Atrix when i sold that.

* edit looking into the wiping system part to see exactly what it erases.
Wiping system, factory reset, cache and dalvik should erase everything except storage. You could wipe internal storage after you freshly install a ROM. But hopefully there are no errors, because you will have no files on storage if something had went wrong during installation. I would also have a ROM file on an external sdcard that you could plug in if you needed to.
You will probably want to leave one ROM file on the device for the person you are selling it to, just incase.
Sent from my Nexus 5

stelv said:
* edit looking into the wiping system part to see exactly what it erases.
Wiping system, factory reset, cache and dalvik should erase everything except storage. You could wipe internal storage after you freshly install a ROM. But hopefully there are no errors, because you will have no files on storage if something had went wrong during installation. I would also have a ROM file on an external sdcard that you could plug in if you needed to.
You will probably want to leave one ROM file on the device for the person you are selling it to, just incase.
Sent from my Nexus 5
Click to expand...
Click to collapse
Well, I am selling it with the 8GB Micro-SD card anyway, since i've got no use for it with the Nexus 5. And i believe that's what i did with the Atrix. Wiped storage/system/factory reset/cache. Pretty much everything that made sense to wipe.... and just kept the ROM on the SD card out of the phone, just to make sure i didn't accidentally wipe that somehow.
And i'll probably just do what i usually end up doing for stuff like this. Wipe everything, install the ROM and make sure it boots, and just shut it off when it comes to the initial setup screen.

Here are some useful links
http://forum.xda-developers.com/showthread.php?t=1823906
http://teamw.in/whattowipe
Sent from my Nexus 5

What partitions do I wipe to reflash stock?

Heya! Thanks for taking the time to read this!
I'm trying to flash the NAND backup of stock I made in TWRP before flashing a custom Rom. I'm just wondering which partitions (in TWRP) I should wipe before restoring the backup?
In Advanced Wipe, the following partitions are listed:
-Dalvik Cache
-Cache
-System
-Data
-Internal Storage
-MicroSDcard
-Android Secure
-USB-OTG
-SD-Ext
In the past I have flashed my Galaxy S2X and S3, and for those phones, the first 4 were all that needed to be wiped. I assumed it would be the same for the M8, but wanted to ask first as I couldn't find it listed anywhere to be sure.

JohnHorus said:
Heya! Thanks for taking the time to read this!
I'm trying to flash the NAND backup of stock I made in TWRP before flashing a custom Rom. I'm just wondering which partitions (in TWRP) I should wipe before restoring the backup?
In Advanced Wipe, the following partitions are listed:
-Dalvik Cache
-Cache
-System
-Data
-Internal Storage
-MicroSDcard
-Android Secure
-USB-OTG
-SD-Ext
In the past I have flashed my Galaxy S2X and S3, and for those phones, the first 4 were all that needed to be wiped. I assumed it would be the same for the M8, but wanted to ask first as I couldn't find it listed anywhere to be sure.
Click to expand...
Click to collapse
in my case I just wipe
-Dalvik Cache
-Cache
-System
-Data
this will "factory reset" your phone, but keep the Internal Memory intact

Just wiping cache and Dalvik should be fine.
I believe system and data will be wiped automatically and your nandroid data restored to those partitions. No need to do it manually. Although it probably don't hurt to do so; and may even be prudent to avoid random issues.
But in fact, I'm pretty sure I've restored nandroids without wiping anything, and it worked fine.

Unsure how to properly wipe without wiping internal storage

Hello all,
Sorry for this semi-noob question. I have had many android phones and rooted all of them but this is my first Nexus device. I've unlocked my bootloader and have TWRP installed and I'm ready to install a ROM. Unfortunately I am unsure of how I can do a full wipe without wiping my internal storage too.
On every other phone I have had, I would go to advanced wipe and then wipe system, data, cache and dalvik cache but I just did that and it wiped my internal storage :/
I had to flash the stock system image through ADB because ADB sideload wasn't working. Now I'm afraid to wipe system again before trying again because I feel like it will wipe my internal storage again. How can I wipe system properly before installing a new ROM?
Thanks!

Now the interesting question here is: What is internal storage?
You seem to think it is the entire emmc, including your system, cache and data partitions but that is not how that term is used.
As far as I have been able to figure this out "Internal Storage" in Android refers to the entire /data partition which in itself again is divided into a user accessible part where your photos, videos, files are stored ( /data/media and mounted as /sdcard/0 ) and the rest of the /data partition which is used for apps you install and their data. That part is not accessible to the user unless you have root.
Now, for 99% of all wipe operations all you need to do when installing a new rom is to wipe the data partition of all user installed apps and their data, dalvik and cache - also called a 'clean install'.
Any rom installer worth a damn will format /system before installing a new rom, so wiping /system is redundant.
TWRP made this very easy: Enter the Wipe menu and swipe the button. Default is to wipe /data (without wiping /data/media), cache and Dalvik. Flash the rom - done.

berndblb said:
Now the interesting question here is: What is internal storage?
You seem to think it is the entire emmc, including your system, cache and data partitions but that is not how that term is used.
As far as I have been able to figure this out "Internal Storage" in Android refers to the entire /data partition which in itself again is divided into a user accessible part where your photos, videos, files are stored ( /data/media and mounted as /sdcard/0 ) and the rest of the /data partition which is used for apps you install and their data. That part is not accessible to the user unless you have root.
Now, for 99% of all wipe operations all you need to do when installing a new rom is to wipe the data partition of all user installed apps and their data, dalvik and cache - also called a 'clean install'.
Any rom installer worth a damn will format /system before installing a new rom, so wiping /system is redundant.
TWRP made this very easy: Enter the Wipe menu and swipe the button. Default is to wipe /data (without wiping /data/media), cache and Dalvik. Flash the rom - done.
Click to expand...
Click to collapse
"Internal Storage" as I used the term refers to just the user accessible part of the data partition where (as you said) photos, files, etc are stored. On previous versions of TWRP for phones I have had, you could wipe system, date, cache, etc and it would always leave internal storage intact. Ergo, after wiping, you could navigate to your downloads folder and find the ROM you wanted to flash. The issue I had was that I wiped "system" using TWRP and it wiped my "internal storage", meaning my downloads and photos and everything - leaving me with no ROM to flash.
You answered my question perfectly toward the end with this
Any rom installer worth a damn will format /system before installing a new rom, so wiping /system is redundant.
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Click to collapse
I come from a series of phones where this was not standard behavior for ROM installers, so failing to wipe system would lead to a dirty flash and almost assuredly cause issues. Thanks for the input, I will just do a data wipe from now on.

You shouldn't count on roms wiping system automatically.
A well established rom like pure Nexus for instance does not wipe system at flashing, leaving it up to the user to clean or dirty flash.
Always read and follow the installation instructions that come with the rom and you should have little problems. If there aren't any instructions, stay away from the rom is my advice, especially of you are a new user.
As to your question: go to the wipe menu in twrp. Then do an advanced wipe. Check every box except internal storage and wipe. Then proceed to flash your rom.

peltus said:
You shouldn't count on roms wiping system automatically.
A well established rom like pure Nexus for instance does not wipe system at flashing, leaving it up to the user to clean or dirty flash.
Always read and follow the installation instructions that come with the rom and you should have little problems. If there aren't any instructions, stay away from the rom is my advice, especially of you are a new user.
As to your question: go to the wipe menu in twrp. Then do an advanced wipe. Check every box except internal storage and wipe. Then proceed to flash your rom.
Click to expand...
Click to collapse
Thanks, I'm not a new user by any stretch, just new to the Nexus 5x.
As to your question: go to the wipe menu in twrp. Then do an advanced wipe. Check every box except internal storage and wipe. Then proceed to flash your rom.
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Click to collapse
This is exactly what I did when it wiped the ROM file (and all photos/sms backups) from my internal storage. That's how I have always wiped before flashing a new ROM in TWRP and this is the first time it ever wiped my internal storage, hence my question. I think I'll just stick to ROM installers that perform a system wipe. I plan on running the odex stock based ROM I just installed for a while anyway.

The_mamba said:
Thanks, I'm not a new user by any stretch, just new to the Nexus 5x.
This is exactly what I did when it wiped the ROM file (and all photos/sms backups) from my internal storage. That's how I have always wiped before flashing a new ROM in TWRP and this is the first time it ever wiped my internal storage, hence my question. I think I'll just stick to ROM installers that perform a system wipe. I plan on running the odex stock based ROM I just installed for a while anyway.
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Click to collapse
Sorry for assuming you're a newby. Last time i wiped that way in twrp (June 2016) it left my SD card alone. Maybe you checked the wrong box?

peltus said:
Sorry for assuming you're a newby. Last time i wiped that way in twrp (June 2016) it left my SD card alone. Maybe you checked the wrong box?
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Click to collapse
No worries, I appreciate the help either way. I suppose it's possible I checked the wrong box but I am very diligent about that because I have REALLY screwed myself over with that in the past. I accidentally wiped internal storage once or twice on my HTC One and had to RUU back to stock, losing everything including root. Luckily recovery is quicker and easier on the 5x (and the phone is brand new so it had no pictures on it).
I'm afraid to try it again even with a nandroid since the recovery files or stored on internal storage so wiping that would leave me SOL too. Like I said, I'll probably just ride on this ROM until the Nougat or so and then make a full cloud backup before trying a full wipe again.

Wiping system did not erase your files. /system is read only, so you nor your apps can store anything there.
I respectfully disagree with @peltus. In those parts of XDA where I "grew up" a dirty flash is a rom flash without wiping data. And I would be grateful for a link to a rom where the installation script does not involve formatting or wiping /system.
I could be wrong but I believe TWRP's wipe of data is without data/media.
Internal Storage wipes the entire data partition.
One if these days with more time I'll give it a try
Sent from my Nexus 5X using Tapatalk

BONUS: What is a data/media device?
https://twrp.me/faq/datamedia.html
The relevant part:
Since /data/media is part of /data, we pretty much never actually format the data partition. Formatting data, of course, also removes the media folder that contains the internal sdcard. When you choose a factory reset [or wipe data], instead of formatting, we use rm -rf commands to remove all the folders except for the media folder so that we can remove all of your apps and settings while leaving your "sdcard" intact. In TWRP we also have a wipe internal storage option that rm -rf's the media folder and a "Format Data" option that formats to recreate the entire file system in case something goes completely wrong or to remove device encryption.
Click to expand...
Click to collapse
[ ] - added by me.

[Guide] What to wipe or format: the case of an upgrade or a completely different ROM

I feel like explaining this somewhat more extensively as it was not clearly documented somewhere. In the case of a totally new and different ROM (so not an upgrade to a newer version which the ROM developer stated as safe for upgrading), you should wipe the following partitions:
/system (where your ROM resides)
/data (without /data/media if you want),
/cache (probably not needed though as it does not contain a whole lot usually).
When upgrading, if deemed possible, you don't format anything, and flash the new ROM over the old one. In many ROMs, /system will usually still be erased/formatted by the flashing procedure. However, most ROMs automatically reinstall Gapps, root, F-Droid etc. through an addon.d script specifically designed for ROM upgrades, which is convenient when upgrading. When flashing a totally new ROM, erasing /system yourself is hence not strictly necessary, but to make sure the old ROM packages do not interfere with the new one through addon.d, it's best to erase it before flashing.
In TWRP, this formatting for a new ROM goes as follows:
You can simply perform a "factory reset" in TWRP (which deletes most of /data, the Dalvik cache in /data and /cache). Now your settings and apps are removed. Your user data in the internal storage is untouched, which is actually at /data/media, a.k.a. /sdcard where it is mounted too. Then format /system via advanced wipe.
For the same result, you can also just via the "advanced wipe" wipe data, Dalvik cache, cache and system.
Alternatively, choose "format data" (which then wipes /data completely, including internal storage (/data/media) as well as Dalvik cache) and wipe /cache and /system) via "advanced wipe".
For the same result, you can also just via the "advanced wipe" wipe data, Dalvik cache, cache, system and internal storage.
You can leave the other partitions (such as modem partitions, persist, preload (unless your new ROM uses it), EFS, boot (since the kernel is updated by your new ROM) and a few others). In fact, most of these you cannot even format using TWRP.
Note that a factory reset in a custom recovery is usually different from the factory reset in the stock recovery (confusing, I know): it only deletes /data (without /data/media) and cache. In the original recovery it formats /data completely (similar to the "format data" option in TWRP).
See also here and here.
BTW some people on this forum seem to think you should wipe things several times, like wiping the floors ...
Of course, that's nonsense. Flashing too: it should only be done once. These bits are digital people!