Optiboot on Baby Orangutan

Hey all,
I was wondering how I could modify or get a modified version of Optiboot for a 20Mhz Baby Orangutan? It's still an ATMega328P, so I would think it wouldn't be hard. I'm not sure what I need to recompile and where, but I imagine it's not much more than changing F_CPU?

Thanks in advance for any help provided.