Did some reverse engineering of the TMC2208 on the CR10s Pro Creality v2.4 motherboard to enable linear advance.
Here is a quick guide on how to mod your Creality motherboard to enable the UART on the TMC2208 of the extruder.

By the way... there is a design flaw with the TMC2208 connections on this board. The three TMC2208 pins PDN_UART, DIAG and INDEX are all connected together and pulled up by a 100k resistor to +5V. That way the INDEX and DIAG ouputs are working against eachother....