All About Recovery Images
A quick summary
Recovery is a limited boot mode, independent of your normal Android operating system. In recovery, you can backup, restore, install packages, wipe data, and do limited troubleshooting of Android. The featureset available depends on the specific recovery installed. In general, stock recoveries (which come pre-installed on your device) are the most limited. They typically only allow manufacturer updates to be performed and remain mostly invisible to the end user. Simple recovery, used by the CyanogenMod Installer, is another limited recovery meant to perform only basic tasks, like updates and data wipes. Custom recoveries, described below, offer a much larger suite of tools. The most important of these is the ability to make a full device backup which can later be restored if Android misbehaves in an unrecoverable fashion. Apps like GooManager and ROM Manager rely on these more feature rich custom recoveries to accomplish many of their tasks.
For specific instructions about how to install a custom recovery, see the wiki page for your device. Some devices have several custom recoveries available, while others have only one (or none!). Some of the more popular recoveries include:
ClockworkMod Recovery (CWM or CWMR) - This is one of the original custom recoveries that is still widely used today. Most of its functionality was written by Koushik Dutta (Koush), but it has since seen significant code contributions come from the community via CyanogenMod's code review. Several variants are available, including: standard (hardware keys navigate the menus), swipe (basic up/down/left/right navigation by swiping), and touch (fully touch-driven menus).
TeamWin Recovery Project (TWRP) - This is another very widely used custom recovery. It is fully touch-driven, has one of the most complete feature sets available, and uses a themable UI. TWRP is maintained by Ethan Yonker (Dees Troy) and sees a number of contributions from the community via OmniROM's code review.
PhilZ Touch - This recovery has gained popularity over the last couple years. Written by Phyto Wardt (Phil3759), it is taglined "CWM Advanced Edition". Indeed, it uses ClockworkMod as its base and extends it with more filesystem tools and a custom user interface. Some of the changes made to PhilZ Touch are later submitted by the author for inclusion in ClockworkMod.
Starting into recovery mode
There are several methods for booting into recovery:
Advanced reboot menu - If your device is already running CyanogenMod, you can enable an advanced power menu that will enable you to reboot directly into recovery:
- Enable developer options
- Settings > Developer options > Advanced reboot = On
- Hold the power button to see the reboot menu
ADB - If ADB is installed on your computer, you can use the command:
adb reboot recovery
Terminal App - If you have superuser access (root), then from the Terminal app, you can use the following commands:
Manual method - Every device has a way to boot into recovery mode, or a special bootloader, by holding down a special combination of buttons when the device is first started. Consult the info page for your device for the correct combination.