That's interesting hardware for OpenWRT!
The ODROID H2 Net card brings 4 additional 2.5 GbE Ethernet ports for an incredible low price. It is compatible with the H2, H2 rev. B and H2+. Using a H2+ you end up with a total of 6 x 2.5 GbE Ethernet ports. With the H2 and H2 rev. B you get 2 x 1 GbE and 4 x 2.5 GbE Ethernet ports.