Note: This is not an Official Firmware,it’s a Custom ROM and will void your device warranty.
Before we start the process,make sure you have backup all your phone data,for example: media,contacts,sms,etc....
Here are some guidelines that you should follow:
•Use this tutorial only on Samsung Galaxy S3 U.S. LTE,don’t try it on other device not even on non-LTE SGS3 phones.
•Your device should be Rooted and have Custom Recovery .
•Read the entire tutorial before starting the process.
•Go to Developer Option Menu and enable USB Debugging.
•Make sure your phone battery is fully charged.
Now, lets see the important steps:
* INSTALL ANDROID 4.4.4 CM11 M9 KITKAT CUSTOM ROM ON YOUR Samsung Galaxy S3 U.S. LTE:
•First you have to Download CM 11 M9 Android 4.4.4 ROM And
Gapps. on your computer.
•Now connect your device using a USB cable and copy/paste the files in the root directory of your phone, or you can download it directly to your phone internal SD card.
•Disconnect your device and turn it off.
•Now boot your device in Recovery Mode,you can enter Recovery Mode by pressing Home+power+Volume up button simultaneously.
•Once in Recovery Mode select “wipe data/factory reset” and “wipe cache partition” to clear your device.
•You can also do “wipe dalvik cache” from the advance menu in CWM recovery(Recommended).
•Head back to the main menu and select “install zip from SD card” and select the Firmware file from your SD card and hit install.
•Repeat the same process for Gapps ( “install zip from SD card”)…
•After the installation process complete, Go back to the main menu and select “reboot system now”,it will take around 10 minutes to start for the first time.
That’s it , you have successfully updated your Samsung Galaxy S3 U.S. LTE with the ANDROID 4.4.4 CM11 M9 KITKAT CUSTOM ROM. If you have any queries or facing any problem feel free to ask me in the comment section and not forget to share this.