Mod edit:
Note: this guide is for rooting Android 4.0.x ICS (Ice Cream Sandwich) version of Android for the VZW SGS3.
Please see this post if you are looking for information on how to root an Android 4.1.x JellyBean device:
Cheers and thanks to Rolo42 for making this original guide for everyone!
-SA
This guide contains soup-to-nuts step-by-step procedures for rooting and/or flashing your Verizon Samsung Galaxy SIII (SCH-I535). If you follow these instructions precisely, everything should work fine. If it doesn't, report precisely what you did and precisely what the outcome was as well as any other relevant information--help us help you.
The usual disclaimer: You are responsible for your actions and the consequences.
First and foremost, to get your phone to talk to your PC, you will need the Samsung drivers for Windows:
1. Download: Link
2. Install
3. Reboot
4. Plug your phone into your PC, let it find/configure drivers
5. Test: open Windows Explorer, click on "Computer" to see if your phone is listed as a device; browse it
Rooting
There are two methods to root your phone. The first method involves no flashing and uses Android Debugging Bridge (ADB) to root and install the requisite superuser app. This method does not require clearing caches or resetting and it leaves everything intact.
Method 1 (no flash)
1. Ensure aforementioned Samsung USB drivers are working properly
2. Download Noxious Ninja's DebugFS root tool from here: Link
3a. If you do not have ADB installed (from Android or mini SDK--if you don't know what this is, you haven't installed it; cf. http://androidforums.com/faqs/443072-adb-guide-updated-12-05-2011-a.html), extract DebugFS root tool into its own folder (i.e. "C:\root"); I like 7-zip archive program
3b. If you have already installed ADB or the Android SDK, extract DebugFS root tool into your ADB folder but do not replace any files!
4. Open Windows Explorer, browse to your newly extracted DebugFS folder (i.e. "C:\root")
5. Double-click on "RootDebugfs.bat" and follow the directions
6. After the batch file completes, open the Superuser app; set your options per your preference. You now have root access.
The second method is flashing an already-rooted stock ROM. This method is useful when wiping your phone (to install a new custom ROM perhaps) and for updating your firmware to VRALG1**. Additionally, this method eliminates the "Custom" unlocked lock icon boot screen ("tripwire").
**Update: VRALG7 is current version via OTA; rooted ROM download and procedures are here: Download Verizon Galaxy S3 VRALG7 OTA Update, already rooted and deodexed!
Method 2 (flash)
1. Ensure aforementioned Samsung USB drivers are working properly
2. If you do not have a torrent client installed, download/install one now; I like Tixati
3. Download VRALG1 full firmware from this post: Link
4. Double-click the .torrent file you downloaded in step 3; your torrent client should search/download the ROM (.tar.md5 file)
5. Unplug the phone from the PC and power it off
6. Download, install and run Odin: Link
7. Put the phone in download mode: press and hold volume down, home, and power buttons until the screen displays a prompt
8. Press volume up to continue
9. In Odin, verify the "ID:COM" section shows a COM port (the first rectangle)
10. It doesn't because I forgot to tell you to plug in the phone
11. Plug the phone into the PC
12. Now verify the "ID:COM" section shows a COM port connected
13. Click "PDA" and select the VRALG1 firmware (.tar.md5 file)
14. After Odin verifies MD5 hash, press Start button; if MD5 check failed, delete the file, re-download it and try again. You are now rooted.
15. Optional: Install EZ Recovery from the play store. Flash a custom recovery of your choice (I like TWRP2.2)
16. Reboot into recovery (if you didn't install EZ recovery or don't have an app to reboot into recovery, power off; then hold volume up, home, and power keys to boot into recovery)
17. Clear cache and Dalvik cache.
18. Reboot & enjoy! NOTE: The first boot after any wipe takes a long time; be patient.
Unlocking the Bootloader
Unlocking the bootloader does three things:
- Enables you to flash custom kernels without kexec workarounds
- Clears the "Custom" unlocked padlock notification on boot
- Decreases boot time since it no longer performs security checks
NOTE: This is not required for either rooting or flashing a kexec kernel/ROM or the aforementioned VRALG1 ROM in Method 2.
1. If you do not have root access, root your phone per above procedure
2. Install EZ-Unlock app from the Playstore: Link
3. Run the app, press the Unlock button
4. Reboot to ensure all is well!