I have read in many guides that before flashing, we need to have a custom recovery like CWM installed. I am not able to understand why is this a prerequisite for flashing a custom ROM. Can I flash a ROM without custom recovery?

2 Answers 2


Stock recoveries usually check the update.zip file being flashed for a specific signature that is only known by device's manufacturer and/or carrier. You cannot therefore flash custom ROMs on stock recoveries, hence the need for a custom recovery which bypasses said check.

  • Yet sometimes the signature can be kept intact or forged. In those cases the stock recovery will do fine. For example you can flash a new recovery using the stock recovery with a SGN n7000.
    – jiggunjer
    Commented Dec 2, 2015 at 5:41

Technically, it's not prerequisite, but convenience.

You can download an update using your handset and store it locally on the sdcard, then reboot manually into recovery. Or use Rom Manager to do all that in an app and enjoy backup/restore and OTA updating without the need for a computer.

Stock recoveries won't let you do all the fancy stuff that a custom recovery let's you do.

Among them are:

  • backup/restore
  • using adb in recovery mode
  • flashing custom .zip's (that's what you'll need)
  • format individual partitions
  • wipe individual parts (Dalvik Cache, /Cache)

Some handset makers have their own means of low level access to flash. Fastboot then has not all needed commands built in.

  • HTC/Google/others: fastboot
  • Samsung: fastboot, proprietary (Heimdall open source flash tool)
  • Sony / SonyEricsson: fastboot, proprietary (Flashtool by Androxyde)
  • ...
  • U said that it is just a convinience, but is there a possibility that the stock recovery will not allow the flashing of an update if it is not signed? In that case it is a necessicity rather than a convinience right? Commented Jun 22, 2012 at 6:53
  • Yes, stock recoveries won't allow that (often). You can use other means besides any recovery to flash images (Heimdall & Flashtool being 2 of them). So for Sony & Samsung you can bypass to use a recovery (theoretically)
    – ce4
    Commented Jun 22, 2012 at 7:15
  • why do you call odin fastboot?
    – jiggunjer
    Commented Dec 2, 2015 at 5:44

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