Install Android 8.0 Oreo on T-Mobile Galaxy S3 SGH-T999 via Lineage OS Custom ROM

Lineage OS team proudly presents their latest build of custom firmware which is based on Android 8.0 Oreo for T-Mobile Galaxy S3 SGH-T999. So if you own the T-Mobile Galaxy S3 and want to get the experience of latest Android 8.0 Oreo then you must install this amazing Lineage OS custom ROM on your device because there is no news about an official update for your device by Samsung. This latest custom firmware comes with tons of new features and customizations. The ROM is under development so you may face some bugs but the good thing is that you can test the Android 8.0 Oreo on your own device. This ROM is not officially announced by Samsung but just a custom ROM which is developed by the third-party developers. Your device must be rooted and installed with the latest version of a custom recovery like TWRP or ClockwordMod (CWM). Lineage OS custom ROM required a custom recovery in order to flash the ROM on your Galaxy S3 SGH- T999.

By following this step by step guide, you can easily and quickly update your T-Mobile Galaxy S3 SGH- T999 to Lineage OS custom firmware. This latest custom firmware is very stable, fast and smoothly run on your device. The official update is good but custom firmware gives you more features and you can customize your device. Before proceeding, don’t forget to take the full backup of all your valuable data. If you are interested in installing Lineage OS Android 8.0 Oreo custom ROM on your T-Mobile Galaxy S3 SGH-T999 then go ahead and follow the given steps.

T-Mobile Galaxy S3 update Android 8.0 Oreo Lineage OS Custom ROM 11


The Lineage OS Android 8.0 Oreo custom ROM and instructions given in this guide can be used only for the T-Mobile Galaxy S3. Check the model number of your Galaxy S3 from Settings > About Phone.


AndroidBlog will not be held responsible for any kind of damage occurred to your T-Mobile Galaxy S3 during or after the installation of Lineage OS Android 8.0 Oreo ROM. Proceed at your own risk SM- T999.


  • Create a proper backup of all your existing data and settings on the phone before moving on to the installation guide using a recommended custom recovery.
  • Enable USB Debugging Mode on the T-Mobile Galaxy S3 by navigating to Settings > Developer Options.
  • Verify that you’ve correctly installed the Galaxy S3 USB Drivers on the PC.
  • The Galaxy S3 should be rooted with the latest version of the custom recovery like CWM or TWRP installed.
  • The bootloader of your S3 must be unlocked.
  • Make sure that the battery level of the Galaxy S3 is at least above 80% before going ahead.

Required Files:

Steps to Install Android 8.0 Oreo Lineage OS Custom ROM on T-Mobile Galaxy S3:

Step No 1: – First, download Lineage OS Android 8.0 Oreo custom ROM for T-Mobile Galaxy S3  on the desktop of the PC.

Step No 2: – Plug your device to the PC using its USB data cable and mount its USB memory storage.

Step No 3: – Transfer Lineage OS Android 8.0 Oreo ROM .zip file which you’ve already downloaded from the above link to the root folder of your SD card on the phone.

Step No 4: – Unplug the Galaxy S3  from the PC and power it OFF to boot into Recovery Mode.

Step No 5: – Power ON the device while pressing and holding Volume Up + Home + Power buttons at the same time to enter into Recovery Mode.

Step No 6: – While your device is now in CWM Recovery, perform wipe data/factory reset, wipe cache partition and wipe dalvik cache also by navigating to Advanced > Wipe Dalvik Cache.

Note: – wipe dalvik cache will help you to prevent boot loops and other errors during ROM installation.

Step No 7: – Go back to the main Recovery Menu and choose to install zip from SD card → choose zip from sd card.

Step No 8: – Navigate to the Lineage OS Android 8.0 Oreo custom ROM .zip file which you’ve already transferred to the SD card of your device previously. Select the ROM .zip file using the Power button and confirm the installation to begin.

9: – Navigate to +++++Go Back+++++ once the installation is completed. From Recovery Menu, reboot your device by selecting reboot system now.

Your Galaxy S3  will be reset and may take about 4 to 5 minutes to boot for the first time after installation.

Done! You’ve successfully updated T-Mobile Galaxy S3 to the latest Lineage OS Android 8.0 Oreo ROM.

Bhatti Junaid

He continuously writes tech articles and development code. Also, appreciates excellent food, exceptional coffee and great company. He has written 266 guides and other posts.

Related Articles

One Comment

  1. does this really work? the file you point to is for the galaxy s2 phone, your saying to use that file on the s3? i don’t mean to doubt you but i don’t want to end up bricking my phone with file that was meant for s2 instead of s3 … anyone else actually try this? linage-OS don’t have a version for sgh-t999 yet

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button