The following raw commands will surely prove useful to the next person who reads this topic. I got these directly from Supermicro support. Cheers:
To get LAN mode: ipmitool raw 0x30 0x70 0x0c 0.
To set LAN mode dedicated: ipmitool raw 0x30 0x70 0x0c 1 0.
To set LAN mode onboard/shared: ipmitool raw 0x30 0x70 0x0c 1 1.
To set LAN mode failover: ipmitool raw 0x30 0x70 0x0c 1 2.
These raw values will also work with ipmicfg (just remember to use -raw instead of raw).
After setting the required LAN mode, do not forget to do a hard reboot.