There is a way....I am currently running 2.0 firmware and playing homebrew with out having to downgrade. There is an eboot loader for the 2.0 firmware. Go to
www.pspupdates.com. In the forums section, under homebrew/development there is a sticky that explains this method and what you'll need. It currently runs only a handful of homebrew but it still allows me to play my NES and SNES on my PSP. Any Kernal based homebrew isn't supported yet, such as UMD Loaders. Hope this helps.