How to Unroot Samsung Galaxy Alpha AT&T SM-G850A

This guide walks you through removing root access from the Samsung Galaxy Alpha AT&T (SM-G850A), returning it to a fully stock, unrooted state. This is useful for restoring warranty eligibility, receiving OTA updates, or fixing apps that detect root. You will need a Windows PC, the original USB cable, and the specific firmware files for your model.

What You’ll Need

• A Windows PC (Windows 7 or newer)
• The original Samsung USB cable
• Odin 3.10.7 or newer (download from a reputable source)
• Samsung USB drivers installed on your PC
• The stock firmware file for SM-G850A (AT&T) — usually a .tar.md5 file
• A full backup of your phone’s data (this process wipes everything)

Step-by-Step

1. Back up your phone. Since unrooting via Odin will wipe all data, back up photos, contacts, messages, and any other important files to your PC or cloud storage. Use Samsung Smart Switch or a manual copy to a computer.
2. Enable Developer Options and USB Debugging. On your phone, go to Settings > About Phone and tap Build Number 7 times. Then go to Settings > Developer Options and turn on USB Debugging.
3. Download the correct firmware. Search for “SM-G850A firmware” on sites like SamMobile or Updato. Make sure you download the AT&T version for your exact model (SM-G850A). The file will typically be a ZIP containing a single .tar.md5 file. Extract it to a folder on your PC.
4. Install Samsung USB drivers. If you haven’t already, download and install the Samsung USB Driver for Windows. Restart your PC after installation.
5. Extract Odin. Download Odin 3.10.7 (or newer) and extract the ZIP to a folder. You should see Odin3.exe inside.
6. Boot your phone into Download Mode. Power off the phone completely. Then press and hold Volume Down + Home + Power buttons simultaneously. When the warning screen appears, press Volume Up to continue into Download Mode.
7. Connect your phone to the PC. Plug the USB cable into your phone and PC. In Odin, you should see a blue or yellow box in the top-left corner showing an “Added!!” message and the COM port number. If you don’t see this, reinstall drivers or try a different USB port.
8. Load the firmware into Odin. Click the AP (or PDA) button in Odin and select the .tar.md5 file you extracted. Do not touch any other tabs or options. Leave all checkboxes as they are (Auto Reboot and F. Reset Time should be checked).
9. Start the flash. Click the Start button in Odin. The process will take a few minutes. You will see a progress bar, and your phone will show a progress bar as well. Do not unplug the cable during this time.
10. Wait for the “PASS” message. When the flash completes, Odin will display a green “PASS!” message in the top-left box. Your phone will automatically reboot. The first boot after flashing can take up to 10–15 minutes, so be patient.
11. Verify root is gone. After the phone boots, go to the app drawer and look for an app called SuperSU or Magisk. If neither is present, root has been removed. You can also install a root checker app from the Play Store to confirm.

Common Mistakes

• Using the wrong firmware file. Flashing firmware for a different model (like the international SM-G850F) will fail or brick your device. Always download the SM-G850A AT&T version.
• Forgetting to back up. Odin flashing wipes all user data. If you skip the backup, you will lose everything.
• Unplugging the cable during flash. This can soft-brick your phone, leaving it stuck on the boot logo. Always wait for the PASS message.
• Not installing Samsung drivers. Odin won’t recognize your phone without proper drivers, and you’ll get a “No device” error.
• Having Reactivation Lock enabled. If you have Samsung’s Reactivation Lock turned on (in Settings > Biometrics and Security), Odin may fail. Disable it before starting.

Tips

• Use a USB port directly on your PC. Front-panel ports or USB hubs can cause connection drops. Use a rear port on a desktop or a USB 2.0 port if available.
• Close all other programs. Antivirus software or background apps can interfere with Odin. Temporarily disable them if possible.
• Keep the battery charged. Ensure your phone has at least 50% battery before starting. A dead battery during flash can cause a hard brick.
• Check the firmware version. If you were on Android 5.0.2 and the firmware you download is Android 6.0.1, that’s fine — it will upgrade your system as part of the unroot process. Just make sure it’s the AT&T build.
• After unrooting, OTA updates should work. Once you’re on stock firmware with no custom recovery, you can receive over-the-air updates normally.

Troubleshooting

Odin says “FAIL!” or “There is no PIT partition.” This usually means the firmware file is incorrect or corrupted. Re-download the firmware from a different source and try again. Also, make sure you’re using the AP slot, not BL or CSC.

Your phone is stuck on the Samsung logo after flashing. This is a soft brick. Boot back into Download Mode (Volume Down + Home + Power) and re-run Odin with the same firmware. If it fails again, try a different USB cable and port.

Odin doesn’t recognize your phone. First, make sure you’re in Download Mode (not just connected normally). Then check Device Manager on your PC for any yellow exclamation marks. Reinstall the Samsung USB drivers and restart your PC before trying again.

Your phone boots but root checker says “not rooted” yet SuperSU is still installed. This can happen if the system partition wasn’t fully overwritten. Re-run the Odin flash, but this time, also wipe the cache partition from recovery mode. To do that, boot into recovery (Volume Up + Home + Power) and select “Wipe cache partition.”

You get an error about “Reactivation Lock.” Go to Settings > Biometrics and Security > Find My Mobile and turn off “Reactivation Lock.” You’ll need your Samsung account credentials to do this. Then re-attempt the flash.

Your phone is completely unresponsive and won’t enter Download Mode. This is rare but possible. Try holding Volume Down + Home + Power for 15 seconds. If that doesn’t work, plug the phone into your PC while holding Volume Down + Home (without Power). If nothing works, you may need a JIG or professional repair — but this is extremely uncommon with the SM-G850A.

Frequently Asked Questions

Will unrooting void my warranty? Unrooting itself doesn’t void a warranty, but the flash counter (if tripped) might. Odin flashing stock firmware resets the counter to zero, so after this process, your phone should appear completely stock.

Do I need to unlock the bootloader first? No. The AT&T Galaxy Alpha has a locked bootloader, but Odin can still flash official stock firmware without unlocking it. This process works with the locked bootloader.

Will this remove TWRP or custom recovery? Yes, the stock firmware file includes the stock recovery. After flashing, your custom recovery will be replaced with the original Samsung recovery.

Can I keep my data after unrooting? No. Odin flashing stock firmware wipes the data partition. There’s no supported way to unroot without losing data on this device. Back up everything first.

What if I only want to unroot but keep the same Android version? That’s fine — the firmware you flash will be the same or newer Android version. You don’t need to downgrade to unroot. Just flash the latest stock firmware for your model.

Is it safe to use Odin on this phone? Yes, Odin is the official Samsung flashing tool (leaked but widely used). As long as you use the correct firmware and don’t interrupt the process, it’s safe. The risk of bricking is very low if you follow the steps.

Related

• Fix Kubernetes Pods Stuck Waiting for a GPU
• Install Firestick Dish Network: Full Setup Guide
• Fix Outlook Mac Error Code? Quick Steps