Upgrade Wallstreet ROM

I have a USB2connect for notebooks made by Adaptec. I am told by Adaptec that my adapter will not work on my Wallstreet. My ROM version is $77D.41F6. Adaptec tells me that "The Rom revision must be $77D.45F1 or later."

Can I upgrade the ROM so I can use USB2 or am I out of luck?

The ROM is basically a firmware update. You can see if there are any updates for your PowerBook, though likely there aren't. That computer is almost 9 years old and there probably aren't any updates that will allow the newer peripheral to work.