Unfortunately, yes
Putting a G partition will work if you choose to just format that drive, however, I would not recommend splitting up the space. When your drive becomes full, it will get annoying when you have 1 or 2 gigs on both drives, with a 3 gig game. You will have to re-arrange just about every time you would want to install another game. I know one person who did that, and after filling both partitions, he asked how to just reformat the drive again to have one giant F partition (I had to, since he doesn't know much about the xbox at all).