Patch Base was updated with support for FB-01, another of Yamaha's classic 4 operator FM synths. There's no way to program patches on the FB-01 alone. Developer Coffeeshopped notes that because of this fact he was able to pick up his FB-01 for just $60!
If you can find one for a similar price, and unlock the FB-01 in Patch Base for $20, you'll have a hardware FM synth for under $100!
What's new in Patch Base v2.2:Yamaha FB-01 Editor now available!
Also, multiple bug fixes for iOS8.
Here is a demo from the developer, noodling around with patches from within the app.