How to Restore OOS After Flashing Oreo ROM on OnePlus 5T

If you’ve flashed an Oreo ROM on your OnePlus 5T, and decide to go back to the stock OOS, you may find you cannot because:

  • The ROM may not read the /data partition, thus hanging on boot animation or simply boots to Recovery Mode.
  • TWRP will not recognize your PIN
  • Formatting /data from TWRP does not solve the issue.

Luckily, we have a method to restore your OnePlus 5T completely back to stock firmware, with factory encryption, which is handled differently than Oreo 8.1 encryption.

Warning: If you have previously flashed OOS OB1/2, you may not be able to revert back to OOS 4.7.x!

Requirements:

ADB Fastboot & Sideloader (See “How to Install ADB on Windows”)

  1. So first you should create a backup of your /sdcard to your PC, as this procedure is going to erase all of your data.
  2. Download one of the stock recovery files from above, depending on your OS version, and place it inside your main ADB folder on your computer.
  3. Now connect your OnePlus 5T to your PC via USB, and launch an ADB command window (hold Shift + right click inside your main ADB folder, and choose ‘Open a Command Window Here’)
  4. Inside the ADB console, type the following command:
    fastboot flash recovery stock_recovery.img
  5. Inside the Recovery menu, choose to ‘Restore System Settings’ – this step is absolutely crucial to restore factory formatting and encryption of the /data partition.

  6. Now reboot into Stock Recovery, and choose Wipe Data and Cache > Reset System Setting > Erase Everything
  7. Now download the TWRP Recovery file from the Downloads section above and place it in your main ADB folder on your computer. Also download the OOS 4.7.6 firmware and place this in your ADB folder as well.
  8. Type into the ADB console:
    fastboot boot twrp-recovery.img
  9. When you’re inside TWRP, type into the ADB command window: adb push OOSxxxROM.zip /sdcard/ (replace xxx with the actual filename)
  10. This is going to push the .zip file to your SD card, its much better we do this via push command instead of transferring it to your /sdcard over USB connection, because we will have to use ADB to boot into TWRP again, so it’s much faster to do it this way.
  11. So once the firmware .zip file has been pushed to your /sdcard, you can now flash it from inside the TWRP menu.
  12. Once its done flashing, choose to Reboot System – your device will be formatted, encrypted, and loaded with the stock recovery and ROM. Basically a complete factory reset.
Kevin Arrows
Kevin is a dynamic and self-motivated information technology professional, with a Thorough knowledge of all facets pertaining to network infrastructure design, implementation and administration. Superior record of delivering simultaneous large-scale mission critical projects on time and under budget.

Expert Tip

How to Restore OOS After Flashing Oreo ROM on OnePlus 5T

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