I am having real trouble configuring mine.

WAN1 & 2 -> enabled always on
WAN 3 -> backup when all failed

WAN1 static IP ethernet 10.1.0.0/16 WAN2 DHCP ethernet (both from conventional thomson routers)
WAN3 static IP 82.108.xxx.xxx/29 internet facing SDSL

I cannot get WAN3 configuration to "stick" unless I choose DHCP client. I cannot get *ANY* sort of IP address to stick in WAN3 (even if I replicate WAN1 settings) - when the 3200 reboots after configuring WAN3 (and I tried WAN4) the configuration resets to "none"

Any ideas?

NVM

factory reset. updated firmware to 3.3.7, factory reset again just in case.

works now.