"Flashing" custom recovery from running ROM

Question

A possible solution to my other question related to this.

Having root access, what's there to prevent me from manually flashing a custom recovery from my running operating system? If my bootloader is locked, can I still do:

dd if=openrecovery-twrp-2.7.0-deb.img of=/dev/block/platform/msm_sdcc.1/by-name/recovery

If so, then I'd be able to flash a custom recovery from inside of a running Android operating system, bypassing a locked bootloader. I suppose if someone has root access to a running operating system, you're pretty much hosed anyway, but would this at least in theory work?

Can I use something similar to the above command to flash a recovery in a live, running Android device?

Answer 1

In response to my own question: yes, you can flash a custom recovery from a running OS. The recovery, since it isn't mounted, should be fine to write:

dd if=openrecovery-twrp-2.7.0-deb.img of=/dev/block/platform/msm_sdcc.1/by-name/recovery

You run the above at your own risk and I accept no responsibility for what you do with this.

Do note, however, that if you have a locked bootloader, it will prevent booting because it will see that the recovery's signature is bad.

Answer 2

A 'newer' and free (and in my opinion the best so far) root app is Flashify. It can flash kernels and recoveries from your phone. Additionally it can download the images for you, too.

https://play.google.com/store/apps/details?id=com.cgollner.flashify

Answer 3

Actually I have tried this on around 3-5 occassions(and it has always worked, for some reason).

What I did was I download recovery in img format (or if it was zip I manually extracted it to get the img file). Then renamed file from whatever name to recovery.img

Then I went to system/etc and deleted existing recovery.img and copied the new one downloaded above. Then set permissions to rw-r-r or 755.

This has quite greatly worked for me. Again, I am not taking any responsibility here. Feel free to backup and check ;)