The Samsung Galaxy Note 9 can now be upgraded to One UI 3.1 and Android 11
Official support for the Galaxy Note 9 has ended, even though the device is more than powerful enough to run Android 11 and beyond. There are already a few custom Android 11 ROMs out there for the former flagship, including an unofficial PixelExperience ROM. However, a developer who posts on the XDA Developers Forums as AlexisXDA has ported One UI 3.1 to the Galaxy Note 9. Please note the ROM is only for the SM-N960F and SM-N960FD variants of the Galaxy Note 9, which means that it will not work on those with Snapdragon SoCs.
According to the pinned forum post, AlexisXDA has ported One UI 3.1 from the Galaxy Note 10 Plus and the Galaxy Note 10 Lite. The ROM, called Noble ROM, currently has the March 2020 Android security patch. Noble ROM can be flashed in TWRP, albeit version 184.108.40.206 of the popular custom recovery rather than version 220.127.116.11. Your device must also have the latest bootloader and modem installed before installing Noble ROM.
The developer warns of two issues with Noble ROM, but none should prevent you from using the Galaxy Note 9 as your main device. The issues are as follows:
- Live Focus does not work currently
- Samsung removed Iris Biometric Authentication and Smart Scan functionality from One UI 3.1, so these are unavailable in this ROM
The developer also expects the ROM to contain some bugs, although only because it is on its first release. He stresses that the ROM has been 'tested for days', so bugs should be at a minimum, anyway. You can download Noble ROM from the XDA Developers Forums.