I found this thread while looking for help getting my 4-wire 12V WS2815 LEDs to work on a Raspberry Pi.
For anyone else looking for the same, the trick was connecting the green Data lead "DI" to GPIO18, the blue "BI" to Ground, and configuring the LEDs in Hyperion as a controller type of "WS281x".
(Sorry about the giant image - I can't find a way of resizing it to something a little less 'shouty'.)
