manage the 4.3 TFT to work on S6.
The Flatcable-connector is useless, because there are two RX - take a look at the schematic of S6.
Covered by the Flatcable-connector J9 is the 4-Pin Header J10.
Take a Look at the Backside of S6 and you see the Pins PC11and PD2 on J10.
The Pin PC11 is routed to Processor Pin79 = PC11/MISO/RX3/4
The Pin PD2 is routed to Processor Pin83 = PD2/RX5
A serial port need RX and TX - here two RX therefor the serial port cannot work.
The TX for RX3 is located above on Pin78.PC10/SCK3/TX3/4
You find PC10 and PC11 on EXP1 too.
Wire by cable to the 4.3 TFT and you have the connection..... 😀
Think about that the TX and RX of the serial port need to be crossed.