Migrate configuration from AMD GX-416RA to AMD GX415GA

[StP]

I have two Deciso A10 appliances. One with a GX416RA SOC, the other has a GX415GA SOC.
The first one is currently active, the second one should provide some redundancy (cold stand-by).
So I want to export the config of the GX416 and load it into the GX415.
As I already found out I have to rename the network interfaces from igb0 to em0 etc.

Now when testing I can connect to the stand-by machine and I see that its WAN interface is connected to the internet.
But not a single data packet is moving from LAN to WAN and vice versa.

What else do I need to change in the config?