OnePlus 6T gets unofficial LineageOS 16, CarbonROM, and more custom ROMs after device seeding program re-opened
Ever since the death of the Nexus program, OnePlus devices have become the de-facto option whenever someone is looking for a developer friendly, yet “cheap” device (though the “cheap” aspect is no longer true). Not only can you easily unlock the bootloader, you also retain warranty after bootloader unlocking, and have access to the kernel sources of the device in a timely manner (which was Day 1 for both the OnePlus 6 and the OnePlus 6T). OnePlus also runs a device seeding program to kickstart custom development works on the device, which gives interested users many more options if they want to customize the software on their phone.
The device seeding program plays an active role in fostering a healthy development community for the device, as can be seen on the OnePlus 2, OnePlus 3/3T, OnePlus 5/5T and the OnePlus 6. OnePlus had recently taken the decision to stop the device seeding program, meaning that it would not send devices to prominent developers. The company clarified that the decision was not permanent, as they were looking to make changes to the selection criterion and communication channels to improve the program. True to their word, the program was re-opened, albeit with a smaller selection of developers.
As a result, we are beginning to see more custom ROMs being made available for the OnePlus 6T. The device has now received unofficial LineageOS 16.0, unofficial CarbonROM cr-7.0, unofficial CypherOS 7.0 and official crDroid. All of these ROMs are based on Android Pie, so you get the latest OS from Google as your base.
The ROMs have their own differentiating factors, so check out their respective threads to know more about their features, installation instructions and bugs. Do note that the fingerprint sensor does not work on these custom ROMs. It is currently unknown if and when this feature will become available.