[Galaxy S III General] davidcsv:
SC-03E Docomo S3 LTE - Just Another Unlocking Guide

This (sim) unlocking guide has been primarily inspired by the very comprehensive guide initially written and posted by [MENTION=301316]majin[/MENTION] in his post.

WARNING: This unlock procedure will automatically wipe the phone's cache and data partitions, effectively performing a factory reset; you are strongly advised to backup your data prior to executing this guide.

Prerequisites:

Windows PC running Odin3 in an administrator account (tested with Odin3 v3.07)

USB cable to connect phone to PC (preferably original cable for reliability)

Internet access to download firmware image(s)

Google account to access Play Store

The following list outlines the required steps in order to successfully unlock your SC-03E:

If you have data on the phone, which is of any importance to you, then I highly recommend that you make appropriate backups first

If present, remove the sim card and sdcard (there's no need to have a Docomo sim card for this procedure to work)

Download this stock firmware image, which is based on MB1 and includes the appropriate modem component to assist in wiping the NV stored network locking data structures. In addition, this firmware image is root-ready; meaning that you can toggle root mode by pressing VolumeUp/VolumeDown/Power button combination briefly to switch modes.

Initiate Odin Download mode on the SC-03E (Turn the phone off, then simultaneously press VolumeDown/Home/Power buttons until the Download Mode splash screen appears and requires you to press VolumeUp to continue or VolumeDown to cancel if you find yourself suddenly struck by an overwhelming feeling of stage-fright)

Unpack the SC03EOMAMB1_LK5MDM.tar.md5 firmware image from the above-mentioned/downloaded zip archive and flash the file with Odin3 (specify the image file in Odin's PDA section)

As soon as Odin completes the flashing process, it will instruct the phone to reset; be patient while the phone starts up, because it will require more time to setup and configure itself after a factory reset.

If you have reached this step, then we're assuming the phone has booted successfully and you are presented with the configuration wizard. You need to at least enter your Google account credentials in order to access the Play Store.

Install the (free) ServiceMode Shortcut app (author: KABASOFT) from the Play Store.

Another (paid) option is the ShowServiceMode For Galaxy LTE app (author: Jaken's Laboratory).

Start the service mode app and tap the ServiceMode option, which will in turn fire up the ServiceMode main menu

Select [1]UMTS->[1]DEBUG SCREEN->[8]PHONE CONTROL->[6]NETWORK LOCK->[3]PERSO SHA256 OFF

Now use the phone's android menu soft button to select Back in the popup menu to return to the NETWORK LOCK menu

Tap [4]NW LOCK NV DATA INITIALLIZ and wait for about a minute before returning to the NETWORK LOCK menu; when you tap this option again, it should state PERSO_NV_INIT is SUCCESSFUL

You may now power off the phone to insert a sim card from your favorite telco operator and restart the phone

From this point onward, it is possible to flash any other firmware image without affecting the unlocked state

Enjoy!