UART0 swap. Use MTCK as UART0 RX, MTDO as UART0 TX, so ROM log will not
output from this new UART0. We also need to use MTDO (U0CTS) and MTCK
(U0RTS) as UART0 in hardware.
However, looking at 0D-ESP8266__Pin_List_v0.1.xlsx I see that function 5 for MTDO is U0RTS and for MTCK is U0CTS and I don't see any option for making these pins TX and RX. Can you please explain? Is one of the two documents incorrect or incomplete?