adb shell su works but adb root does not

Question

I rooted my unlocked Galaxy S3 (SGH-T999)

Now, I\'m trying to run adb root from Windows Command Prompt, however, I\'m getting adbd cannot

Answer 1

By design adb root command works in development builds only (i.e. eng and userdebug which have ro.debuggable=1 by default). So to enable the adb root command on your otherwise rooted device just add the ro.debuggable=1 line to one of the following files:

/system/build.prop
/system/default.prop
/data/local.prop

If you want adb shell to start as root by default - then add ro.secure=0 as well.

Alternatively you could use modified adbd binary (which does not check for ro.debuggable)

From https://android.googlesource.com/platform/system/core/+/master/adb/daemon/main.cpp

#if defined(ALLOW_ADBD_ROOT)
// The properties that affect `adb root` and `adb unroot` are ro.secure and
// ro.debuggable. In this context the names don't make the expected behavior
// particularly obvious.
//
// ro.debuggable:
//   Allowed to become root, but not necessarily the default. Set to 1 on
//   eng and userdebug builds.
//
// ro.secure:
//   Drop privileges by default. Set to 1 on userdebug and user builds.

Answer 2

I have a rooted Samsung Galaxy Trend Plus (GT-S7580).

Running 'adb root' gives me the same 'adbd cannot run as root in production builds' error.

For devices that have Developer Options -> Root access, choose "ADB only" to provide adb root access to the device (as suggested by NgaNguyenDuy).

Then try to run the command as per the solution at Launch a script as root through ADB. In my case, I just wanted to run the 'netcfg rndis0 dhcp' command, and I did it this way:

adb shell "su -c netcfg rndis0 dhcp"

Please check whether you are making any mistakes while running it this way.

If it still does not work, check whether you rooted the device correctly. If still no luck, try installing a custom ROM such as Cyanogen Mod in order for 'adb root' to work.

Answer 3

adbd has a compilation flag/option to enable root access: ALLOW_ADBD_ROOT=1.

Up to Android 9: If adbd on your device is compiled without that flag, it will always drop privileges when starting up and thus "adb root" will not help at all. I had to patch the calls to setuid(), setgid(), setgroups() and the capability drops out of the binary myself to get a permanently rooted adbd on my ebook reader.

With Android 10 this changed; when the phone/tablet is unlocked (ro.boot.verifiedbootstate == "orange"), then adb root mode is possible in any case.

Answer 4

You need to replace the adbd binary in the boot.img/sbin/ folder to one that is su capable. You will also have to make some default.prop edits too.

Samsung seems to make this more difficult than other vendors. I have some adbd binaries you can try but it will require the knowledge of de-compiling and re-compiling the boot.img with the new binary. Also, if you have a locked bootloader... this is not gonna happen.

Also Chainfire has an app that will grant adbd root permission in the play store: https://play.google.com/store/apps/details?id=eu.chainfire.adbd&hl=en

Lastly, if you are trying to write a windows script with SU permissions you can do this buy using the following command style... However, you will at least need to grant (on the phone) SU permissions the frist time its ran...

adb shell "su -c ls" <-list working directory with su rights. adb shell "su -c echo anytext > /data/test.file"

These are just some examples. If you state specifically what you are trying to accomplish I may be able to give more specific advice

-scosler

Answer 5

If you really need to have ADB running as root, the quickest and easiest way is to install Android Custom ROMs and the most popular is CyanogenMod for it has the Root Access options in developer options menu where you can choose to give root access to apps and ADB. I used CM before but since it wasn't developed anymore, I tried looking for some solutions out there. Although CyanogenMod is still a good alternative because it does not have bloatware.

One alternative I found out from a friend is using adbd insecure app which you could try from here: https://forum.xda-developers.com/showthread.php?t=1687590. In my case, it works perferct with an Android custom kernel, but not with the Android stock ROM (vanilla android only). You may try other alternatives too like modifying boot.img of the Android ROM.

Answer 6

I use for enter su mode in abd shell

adb shell "su"