How to Unroot and Return LG Optimus S to Stock

One day you want your LG Optimus S unrooted, never mind, that’s very easy if you follow the instruction below. I’ve tested it on my LG Optimus S, it works without any issue. However, if you encounter some problems with unrooting, feel free to let me know, I will do my best to fix them for you. Now let’s unroot the LG Optimus S.

I have made a nandroid dump of the complete V8 stock system, including kernel, rom, recovery.. everything except the evil devil RADIO. Restoring to V8 will allow you to accept the Sprint V9 update and update your radio PROPERLY.

It will also allow you to bring your phone in for repair, or just remove any hacks you did so you can sell the phone, ect.

This is 99.9% STOCK. This returns your phone to the state it was when you opened the box.

In fact, I pulled this from a brand new LG Optimus S, using the rageagainstthecage exploit, being sure NOT to modify /system in ANY WAY.

However, in order to restore the recovery, I had to use V9’s boot and recovery. This will not effect the upgrade process from V8 to V9 in any way.

Here is what you need to do.
1. Root the LG Optimus S. I assume you are already rooted if you are needing a total system restore.
2. Download GNM’s v1.1.0 Recovery Kernel. Please use this recovery and no other as this is the only one I have tested. Use of another recovery kernel may brick your phone! Your recovery is going to be wiped with LG’s recovery anyway, so don’t risk it!.
3. Download flash_image.
4. Connect your LG Optimus S to your PC and prepare for ADB usage.
5. Unzip the recovery kernel and flash_image.
6. adb push recovery-RA-GNM-thunderc-s-1.1.0.img /sdcard/
7. adb push flash_image /data/local/tmp
8. adb shell
9. su
10. chmod 755 /data/local/tmp/flash_image
11. /data/local/tmp/flash_image recovery /sdcard/recovery-RA-GNM-thunderc-s-1.1.0.img
12. reboot recovery
Now you should be in GNM’s recovery with aqua-colored text. The controls are: Up = VolUP, Down = VolDown, Back = Back, Select = Menu (right of home).
13. Go down to "USB-MS Toggle"
14. Select "USB-MS Toggle SDCard"
15. Download my Stock V8 Nandroid Dump
16. Unzip it into the root of the USB Device/SDCard
17. Safely remove the USB device using your PC OS.
18. Press menu to disable USB-MS Toggle.
19. Press back.
20. Select "Backup/Restore".
21. Select "Nand restore".
22. Select "mem=477M".
23. Select "BCDMRS12-20101122-1915"
24. Press menu to confirm.
25. When the process is complete, DO NOT REBOOT. Nandroid does NOT flash recovery by default, to protect from losing your custom recovery. In this case we WANT to lose it, otherwise we won’t be stock, and OTA updates will not work. Therefore we must…
26) adb shell
27. mount /sdcard (if this throws an error about "device or resource busy", just ignore it) 28. cd /sdcard/nandroid/mem=477M/BCDMRS12-20101122-1915
29. flash_image recovery recovery.img
30. reboot

Now you are back to V8 stock! Enjoy!

To upgrade your LG Optimus S from V8 to V9:
Due to the kernel being from V9, the phone thinks the firmware is up to date, so you will NOT be prompted for the OTA update. However, since I have a copy of it, you can manually install it. Here’s how:
1. Plug phone into PC
2. Enable USB Mass Storage
3. Download the V8 to V9 update and place it in the root of the USB Device/SDCard as "update.zip" (renaming it is important!)
4. run the following from cmd prompt: "adb reboot recovery"
5. You are now at LG’s dark-blue recovery screen (should only be 4 options, if not STOP HERE)
6. Select the option with "update.zip"
7. follow instructions on screen (VERY IMPORTANT)

You now have V9 Radio/Baseband and V9 stock update. You can delete the update.zip from your SDCard when you are back into Android.

Source and Credit to zefie

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5 thoughts on “How to Unroot and Return LG Optimus S to Stock”

  1. Really…. Great…. Fantastic…if you are a NASA tech. Not for the everyday normal cell phone user that just wanted to root a phone…. Need something a little more … let’s say…. EASIER… thanks much anyway…. not for me…

  2. ron.. I can tell you I’m not a NASA tech. I’m only 17 and I understood everything of what he was saying. how did you even root your phone without commands and unzipping?

  3. Tried this with GNM recovery 2.2.1 and now the phone is in a boot loop. Can’t get back to recovery

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