How to solve ADB device unauthorized in Android ADB host device?

Question

When I\'m using a rooted Android device as ADB host to send adb command \"adb devices\" to Samsung S4, I received device unauthorized error message. However when I tried adb

Answer 1

If anyone has similar issue of having a phone with a cracked screen and has a need to access adb:

1. Root your phone (mine was already rooted, so I was blessed at least with that).

If you forgot to enable developers mode and your adb isn't running, then do the following:

1. Reboot your phone into recovery.
2. Connect the phone with a cable.
3. Open terminal.
4. If you type adb devices you should see the device in the list.

5. If so, type:

   adb shell mount /system
   abd shell
   
   echo "persist.service.adb.enable=1" >> default.prop 
   echo "persist.service.debuggable=1" >> default.prop
   echo "persist.sys.usb.config=mtp,adb" >> default.prop
   echo "persist.service.adb.enable=1" >> /system/build.prop 
   echo "persist.service.debuggable=1" >> /system/build.prop
   echo "persist.sys.usb.config=mtp,adb" >> /system/build.prop
   

Now if you are going to reboot into your phone android will tell you "oh your adb is working but please tap on this OK button, so we can trust your PC". And obviously if we can't tap on the phone stay in the recovery mode and do the following (assuming you are not in the adb shell mode, if so first type exit):

cd ~/.android
adb push adbkey.pub /data/misc/adb/adb_keys

6. Hurray, it all should be hunky-dory now! Just reboot the phone and you should be able to access adb when the phone is running:

   adb shell reboot

P.S. Was using OS X and Moto X Style that's with the cracked screen.