Apalis T30 Com3 pin mux config

I am using the WEC7 2.1b2 image with Apalis T30. By default, the transmit pin MXM pin 134 is set to GPIO instead of uart. I have tried various pin configs in the bootloader and registry, with no effect:
apalispin_19
apalispin_134
gpio_18
I am also unsure which altfn selects uart function. Altfn=1, alfn=2 or other?

The info here has been helpful, but I still can’t get it to work.
http://developer.toradex.com/knowledge-base/serial-port-registry-settings
http://developer.toradex.com/knowledge-base/serial-ports
http://developer.toradex.com/knowledge-base/gpio-config-block-settings#Tegra_and_iMX7
http://developer.toradex.com/knowledge-base/gpio-alphanumeric-to-gpio-numeric-assignment

Turns out I was using image v2.0b3. I will try this again with the newer image.