Should I format /sdcard and /data if I want to wipe all personal data with Cyanogenmod?


Question

I'm trying to completely wipe all personal data from my Nexus 4 with CM installed. I've seen different advice on different sites for making sure all my data is gone:




  1. Just do 'Factory Reset'.

  2. Do 'Factory Reset' at least 3 times.

  3. Do 'Factory Reset' and wipe dalvik cache.

  4. ...



and so on... I'm interested in erasing all traces of my personal data from the device. It's a Nexus 4, so there is no removable storage to worry about.



My guess would be to 'wipe data/factory reset' and 'wipe cache partition' in the main recovery menu. In the mount/storage menu, I would choose 'format /cache', 'format /data', and 'format /data and /data/media (/sdcard)'. Finally, in the advanced menu, I would choose 'wipe dalvik cache'.



Is this thorough enough? Should I also choose 'format /system', 'format /firmware', etc? Are there any options I should steer clear from? I would like the phone to boot to a fresh Cyanogenmod after clearing all data.


Answer


Just do 'Factory Reset'.




Well, this depends upon the recovery you're using. If you're using TWRP (assuming you've v2.8.4.x or above), choosing Factory Reset would remove everything under /data (excluding /data/media which serves as emulated storage available through /sdcard as internal SD card), would wipe cache partition, and since davik cache gets stored either in cache or data partition, it would already be wiped out.



If you're using stock Android recovery (<3e>) and choose Factory Reset, then it would format the data partition and cache partition. Davik and internal SD card would also be automatically taken care of by formatting.



If you're using Cyanogen recovery or any other recovery, then I can't comment. I can only suggest switching to TWRP for better control and features.




Do 'Factory Reset' at least 3 times.

Do 'Factory Reset' and wipe dalvik cache.




You only do it one time and that's all you need to do. As I said, a factory reset automatically wipes cache partition so you need not to explicitly wipe it. TWRP notes:




[You] need to [factory reset] and you only need to do it once, not three times as some people would lead you to believe.




As for,




I'm interested in erasing all traces of my personal data from the device




Wiping the partition wouldn't be enough if you're talking about erasing all traces of personal data. There are already Q&A discussed about that on this site, so I'm referring them to you:





Note that if the phone would remain with you after a factory reset/ full data+cache wipe then it is not worth the time engaging in addressing "traces of personal data" since resurrecting deleted data requires physical access to your device.




Are there any options I should steer clear from? I would like the phone to boot to a fresh CyanogenMod after clearing all data.




Yes, please stay away from anything other than /data, /data/media and /cache. System partition doesn't contain personal data and when you would flash your ROM the partition would automatically be flashed because modern ROMs (such as CyanogenMod) do that. Modem partition is mounted at /firmware so it is not worth wiping it out because that may only cause trouble for you.



Related: Won't placing a cuostm ROM file before factory reset remove it from the phone?


Topics


2D Engines   3D Engines   9-Patch   Action Bars   Activities   ADB   Advertisements   Analytics   Animations   ANR   AOP   API   APK   APT   Architecture   Audio   Autocomplete   Background Processing   Backward Compatibility   Badges   Bar Codes   Benchmarking   Bitmaps   Bluetooth   Blur Effects   Bread Crumbs   BRMS   Browser Extensions   Build Systems   Bundles   Buttons   Caching   Camera   Canvas   Cards   Carousels   Changelog   Checkboxes   Cloud Storages   Color Analysis   Color Pickers   Colors   Comet/Push   Compass Sensors   Conferences   Content Providers   Continuous Integration   Crash Reports   Credit Cards   Credits   CSV   Curl/Flip   Data Binding   Data Generators   Data Structures   Database   Database Browsers   Date &   Debugging   Decompilers   Deep Links   Dependency Injections   Design   Design Patterns   Dex   Dialogs   Distributed Computing   Distribution Platforms   Download Managers   Drawables   Emoji   Emulators   EPUB   Equalizers &   Event Buses   Exception Handling   Face Recognition   Feedback &   File System   File/Directory   Fingerprint   Floating Action   Fonts   Forms   Fragments   FRP   FSM   Functional Programming   Gamepads   Games   Geocaching   Gestures   GIF   Glow Pad   Gradle Plugins   Graphics   Grid Views   Highlighting   HTML   HTTP Mocking   Icons   IDE   IDE Plugins   Image Croppers   Image Loaders   Image Pickers   Image Processing   Image Views   Instrumentation   Intents   Job Schedulers   JSON   Keyboard   Kotlin   Layouts   Library Demos   List View   List Views   Localization   Location   Lock Patterns   Logcat   Logging   Mails   Maps   Markdown   Mathematics   Maven Plugins   MBaaS   Media   Menus   Messaging   MIME   Mobile Web   Native Image   Navigation   NDK   Networking   NFC   NoSQL   Number Pickers   OAuth   Object Mocking   OCR Engines   OpenGL   ORM   Other Pickers   Parallax List   Parcelables   Particle Systems   Password Inputs   PDF   Permissions   Physics Engines   Platforms   Plugin Frameworks   Preferences   Progress Indicators   ProGuard   Properties   Protocol Buffer   Pull To   Purchases   Push/Pull   QR Codes   Quick Return   Radio Buttons   Range Bars   Ratings   Recycler Views   Resources   REST   Ripple Effects   RSS   Screenshots   Scripting   Scroll Views   SDK   Search Inputs   Security   Sensors   Services   Showcase Views   Signatures   Sliding Panels   Snackbars   SOAP   Social Networks   Spannable   Spinners   Splash Screens   SSH   Static Analysis   Status Bars   Styling   SVG   System   Tags   Task Managers   TDD &   Template Engines   Testing   Testing Tools   Text Formatting   Text Views   Text Watchers   Text-to   Toasts   Toolkits For   Tools   Tooltips   Trainings   TV   Twitter   Updaters   USB   User Stories   Utils   Validation   Video   View Adapters   View Pagers   Views   Watch Face   Wearable Data   Wearables   Weather   Web Tools   Web Views   WebRTC   WebSockets   Wheel Widgets   Wi-Fi   Widgets   Windows   Wizards   XML   XMPP   YAML   ZIP Codes