How to re root the device samsung galalxy core 2

If you have rooted your smartphone using KingRoot, you can follow the instructions here to unroot your phone first. After your phone is unrooted, you can reroot your device other methods.

If you have used the KingRoot method, your phone will have three apps - KingRoot App, Kingmaster App and KingUser app. Follow the steps below to remove them one by one.
Remove KingRoot and KingMaster apps
Follow the standard method of uninstalling any application. Uninstalling it the standard way will remove both the applications. However, you will not be able to remove KingUser app without making some changes in the app.

Remove Root permissions

• Launch KingUser app.
• Tap on Settings
• Tap on Root Authorisation Settings.
• Tap on Remove Root Permissions
• You should now get a popup stating "Remove Root Permission, and return to unroot status, proceed?"
• Tap on Clear. This will launch unrooting. It will unroot your phone.
• Reboot your phone and you will see that the KingUser application is removed.

You can check that your phone has lost lost root by checking it up with any root checker app.

Once your phone is unrooted, you can now consider rooting your phone again. I would suggest you to root your device using SuperSU app.
Here is how you can do it.

• Make sure you have unlocked your bootloader and have installed a custom recovery like TWRP.
• Go to the link http://www.supersu.com/ and download the latest version of SuperSU in the ZIP format.
• Copy the zip file to the internal storage of your phone. Note down the folder where the file is saved.
• Reboot your device into TWRP recovery. Tap on Install.
• Choose the file by navigating to the folder where you have saved the zip file.
• Tap on file and swipe to confirm.
• Wait till the flashing is completed. Tap on Reboot System

Please note that it will take a while to get your phone rebooted. Wait patiently and check with Root Checker app once done.

Here are the steps required for rerooting the device. So first we are going to unroot and remove kinguser app. And then we are going to use supersu for rooting the device.

Steps for removing Kinguser root settings.

1. Open the Kinguser app.
2. Tap on gear icon to go to settings.
3. Tap on root authorization settings.
4. Tap on remove root permission option.
5. Tap on clear option that says "remove root permission resets and returns unroot status".

After the completion on this process you can uninstall the app. Also do clean any settings files that remained orphan after un-installation of the app.

Before you reroot the device, I suggest taking the device backup. You can use any cloud app for cloning the settings. Also you can take system recovery through various open source tools out there. You can use TWRP for this task.

Rooting using the supersu

1. Download the latest version of supersu through this link : https://download.chainfire.eu/supersu
2. Store the zip file into internal storage of the device.
3. Boot into recovery mode using TWRP or any other recovery mode software.
4. Open the supersu through recovery mode.
5. Flash the device using Wipe cache/Dalvik" button. After that click on Install button and locate the supersu.zip.
6. Let the process finish properly do not press any other button or tap on screen.

After the process finished, you can reboot into the device and it'll show the supersu app in the app drawer. This should let you root and unroot using the supersu app.