[Galaxy S III Q&A, Help & Troubleshooting] MattBooth:
This guide is for reodexing your SGS3, such as UltimaROM, Omega, Foxhound, CodecROM, _null, Sotmax and others (I'm just listing off the top off my head).

It's not terribly tough and 100% of the credit belongs to rujelus22 for his amazing work on his AIO tool. This guide is just for deodexing/odexing, but you can use that tool for other things.

Firstly, why would you want to odex your ROM?

Well, this will help you understand more:

[YOUTUBE]Y_FmiVhC2Jw[/YOUTUBE]

http://www.xda-developers.com/xda-tv-2/pro-tip-number-5-why-you-should-odex-and-deodex-xda-tv/

It's very useful and saves on battery life and makes the phone slightly more responsive.

Consider:

When you have downloaded and installed your chosen ROM you should odex it back up for the speed and agility odexing affords you. However you should ONLY do this after you are happy with your setup. I.E., install any mods you wanted and then Odex your phone.

If you want to add mods later, say, perhaps, your developer releases a new mod, or patch for your ROM you will NEED to Deodex the ROM before applying a patch or new mod. This is important. Please do not pester your dev about an error if you have not done this.

In my opinion, it can take maybe 30 minutes to Deodex, apply your mods/patch, and then Reodex using this tool, but the benefits are worth it.

You should also perform these actions AFTER a successful boot. You should flash the ROM. Boot. skip the setup pages and get to the homepage, then do this odexing.

How to do it:

Firstly, head off over to Rujelus22's AIO script thread and download it:

http://xdaforums.com/showthread.php?t=1955745

Don't forget to click "Thanks"

Make sure you also download these the Android-SDK and the Java Development kit. The SDK is necessary for the Deodexing, I believe, in case you want to do that later:

http://xdaforums.com/showpost.php?p=33268059&postcount=2

After that, extract the AIO script somewhere useful where you can find it again and run the "Start_AIO.bat" file. This will set up some folders in the directory you extracted to and then open the start page

After this make sure your phone is plugged into you computer and that USB Debugging mode is on in the Developers Options. ALSO, you must have an "Insecure Kernel" such as any custom kernel (Siyah, Perseus, Boeffla) or Wanam/zoot1's repacked stock kernel.

If you do not have an Insecure Kernel head off to Chainfire's adbd Insecure thread: http://xdaforums.com/showthread.php?t=1687590

You might considering buying it on Google Play, if you like, but there is a free XDA version.

After you are plugged in, on USB debugging and have an Insecure Kernel, load the AIO script and choose option "22" which reads "Odex the ROM on your phone". You will be given the opportunity to take a nandroid backup at this point.

Sit back and let it do it's thing. It will take about 10 minutes, and it will seem to hang on the clean up bit. Fear not, because it IS doing something. Your phone will automatically reboot when it has finished.

You're done! Once you have done that little bit of setting up... in future it is as easy as opening the script, hitting 22 and sitting back.

Notes/FAQ:

Sometimes it can constantly loop around the first page as though it is doing a first run. To solve this, go into "AIO_FOLDER/tools/Settings/" and create a new .txt file called "firstrun". Make the contents of the file 1. Just "1" and nothing else.

Sometimes it can say that you don't have remount access and the Odex option will not show. Similar to the point above, go into "AIO_FOLDER/tools/Settings/" and make a .txt file called "remount" and place a single 1 in the folder.

Deodexing can take some time. Be patient.