We had a router failure in our office and grabbed our spare 2100 to use for a few days. To use a third interface we isolated port 4.

When restoring the config file to a new 4200, I got stuck when reassigning interfaces in the web GUI. I couldn't delete the VLAN because it was in use on an OPT1 interface (mvneta1, which does not exist on the 4200). However I could not delete the OPT1 interface using mvneta1.4084 because it had a VLAN attached. Is there a way around that loop?

For anyone finding this post later, there are two solutions: one is that Netgate will convert configuration files for you, to/from Netgate hardware. The other is to edit the .xml file to manually remove the VLAN section and assign the interfaces, then restore.