What is recovery? [Android A to Z]

By Jerry Hildenbrand  | Feb 01 2012 | 4:47 pm  | 5 Comments

Android A to Z - Recovery

What is recovery?  In Android, recovery refers to the dedicated, bootable partition that has the recovery console installed.  A combination of key presses (or instructions from a command line) will boot your phone to recovery, where you can find tools to help repair (recover) your installation as well as install official OS updates.  Because Android is open and has the recovery source code available, building a customized version with more and different options is relatively easy as well.  Let's look at both options.

The stock recovery is pretty limited, but that's by design.  Its main purpose is to delete all user data and files, or to perform system updates.  Normally, both these operations are started from the running Android system, or you can do things manually and boot right into recovery yourself.  When you tell your phone to do a factory reset, recovery is what boots up and erases the files and data.  Likewise with updates -- when we restart to install an official OS update, it's done in recovery.  Recovery is also where we go to manually install official OS updates we've downloaded from the Internet.  It's very useful, but limited.

Custom Android recoveries offer much more.  They have been coded to allow for backup and restore functions, selective deletion of data so you don't have to wipe everything, and modified to allow update packages that have not been digitally signed by official sources.  You also can mount various partitions so that you can copy files to the SD card without having to remove it or reboot into Android. Anytime you see someone mentioning Clockwork or Amon Ra, they're talking about custom recoveries.  Because of the extra functionality built in, they are a pretty important tool for folks who want to hack their Android phone or tablet.  Recoveries aren't as pretty as a custom ROM and don't get the same love from users and bloggers that custom builds of Android do, but in the end they're even more important. Without them none of this custom ROM stuff would be possible.  

Previously on Android A to Z: What is a QR Code?; Find more in the Android Dictionary

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There are 5 comments

thacounty says:

Good explanation. Now all we need is Amon Ra back. Oh how I miss his awesome recoveries.

DirkBelig says:

What happened to Amon Ra? I used his recovery on my OG EVO, but only rooted my Galaxy S II Epic 4G Touch Long Name WTFROFLBBQ with ODIN the other day after four months of stock use. Not really shopping for a new ROM - have very few complaints with stock, but wanted to use Titanium Backup - but wasn't aware Amon Ra wasn't still active.

Nosferatu524 says:

Good read as well. (Knock on wood) I've never bricked an Android (can't say the same for other devices).

Question, is there really ever a time that you can't recover a phone via recovery minus say a hardware failure??? I bought a jig as insurance for my phone (Galaxy S2) which throws the phone into download mode no matter what apparently.

donniezazen says:

Is stock recovery used by Google to do development or they have much more sophisticated recoveries like the custom ones?

arnoldprasad-ac says:

I could not find a clear, concise process for resetting to factory set-up so I created this one. My phone is a Samsung Galaxy Nexus.

1)Stop the phone
- Unplug the phone
- Remove the battery
- Put in the battery
- Plug in the phone
2)Restart the phone in RECOVERY mode
- HOLD VOLUME UP + VOLUME DOWN + POWER buttons all at the same time
- The phone should show you a picture with the droid with two arrow keys on where your volume buttons are
- Scroll using the VOLUME BUTTONS to the RECOVERY option
- Then push the POWER BUTTON
- The phone should reboot and then give you a droid on his back with a red exclamation point in a triangle
- At this point press the VOLUME UP + VOLUME DOWN + POWER buttons once and it should take you into the recovery options (you will see a screen with blue text and it should give you the option to wipe data/factor reset)
- Select wipe data/factor reset to factory option (note: you will loose all apps and data)
- When this is completed scroll to the select the reboot system now option using the volume buttons and select this option.
- Your system should restart with the first android screen.