Guide:
In this video, we will show you the steps to install the latest LineageOS ROM based on Android 14 onto OnePlus 9 and OnePlus 9 Pro devices.
Do note that you’ll have to be on the OxygenOS 13 firmware before flashing this ROM [the process to do the downgrade from OxygenOS 14 to 13 has been explained in the video].
00:00 Android SDK Platform Tools
00:30 Enable USB Debugging and OEM Unlock
01:50 Unlock Bootloader
02:21 Download LineageOS 21 for OnePlus 9/Pro
04:52 Boot to Fastboot Mode
05: 49 Downgrade to Android 13/OxygenOS 13
08:39 Flash LineageOS 21 Recovery
10:00 Format Data
10:30 Sideload LineageOS 21 ROM
11:31 Flash GApps [Optional]
14:23 Check out LineageOS 21 on OnePlus 9/Pro