imx7Solo UART_C not working

imx7 running WEC 7 v1.3 ( tried v1.2) clean install from easy installer.
using iris carrier board rev 1.1
.netcf 3.5 installed.

Using a test program to go through each serial port and send data, monitoring outputs on X16
COM1 & COM2 work as expected. normal state is high (3.3v)
COM3 gives no data output. steady state is high (3.3v)

How do i resolve this?

If anyone else has the problem, the solution is as follows.

Colibri pin 21 is listed twice in the registry.
Once for COM3 TXD
and once under USBOTG->Hcd-> Pinout_Default. Remove this and the Serial port works fine.