How to install OctOS Android 7.1.1 Nougat Custom ROM on T-Mobile Galaxy S3 T999


Team OctOS jus released their ROM built on Android 7.1.1 Nougat for T-Mobile Galaxy S3 T999. Galaxy S3 was Samsung’s one of the most successful releases, so Custom ROM developers always try to tweak their releases for this device. This release is packed with usual OctOs features topped with couple of more exclusive features of Android 7.1.1 Nougat.

This is a weekly ROM so it might throw some bugs at you but these will surely be ironed out in final release. Minor bugs shouldn’t hold you back from updating your T-Mobile Galaxy S3 T999. The ROM has Substatum theme engine. Moreover, it has Pixel Launcher, KernelAdiutor-Mod, SuperSU, Volume Button Wake, and Volume button playback control. On the settings front it has Tentacles, Status Bar Notification, Quick tile and DPI settings. Also have Power Menu and Status bar time and date options. You can also record screen or take screenshot.

We have compiled a step by step guide on how to install OctOS Android 7.1.1 Nougat ROM on your Samsung Galaxy S3 T-999 (T-Mobile). Just follow our steps carefully.



  • Your device must be rooted and ClockworkMod recovery must be installed.
  • Before proceeding any further backup all your important data like Emails, Messages, Personal Photos and Videos.
  • Download and install Samsung USB drivers on your Windows PC or Mac.
  • Make sure USB Debugging mode is enabled on your Android Device. You can enable USB Debugging by going to Settings > Developer Options.
  • The device should be charged upto 70% to avoid any unexpected shutdowns. This is very important, any shutdown during the process can damage your device permanently.


Guide on How to Install OctOS Android 7.1.1 Nougat Custom ROM on T-Mobile Galaxy S3 T999

We have tried to keep it very simple, for that reason we have put the guide step by step.

Step 1: Download OctOS Android 7.1.1 Nougat ROM and Google Apps for T-Mobile Galaxy S3 T999 to your computer.

Step 2: Connect your T-Mobile Galaxy S3 T999 with your computer using USB cable.

Step 3: Copy/Paste Android 7.1.1 and files to your SD Card. Make sure to place files on the root of SD Card and not in any folder.

Step 4: Then turn off your device and disconnect from the USB Cable.

Step 5: Now get into recovery mode. Turn On the phone while pressing and holding Volume Up + Home + Power Button together

Step 6: Then in recovery mode perform a full data wipe by selecting wipe Data/factory reset. Use volume rockers for navigation and power button for option selection.

Step 7: Now, go to Advanced Option and clear the cache by selecting wipe cache partition and wipe dalvik cache.

Step 8: After performing Step 6 and 7, navigate back to the main recovery mode screen and select install zip from SD card.

Step 9: Now choose Android 7.1.1 ROM zip file, which you copied to your SD Card, and start the installation process.

Step 10: Repeat the same process for installing Google Gapps after you are done with Step 9.

Step 11: That’s it! Now simply navigate to Recovery Mode Main Screen and select “Reboot System Now”. First boot can take up to five minutes.

You have successfully installed OctOS Android 7.1.1 Nougat custom ROM on your T-Mobile Galaxy S3 T999.