All of the developments here around Froyo are very exciting, and now, as if there's not enough to play with, here's a link to a site that will allow you to run Froyo on your PC: http://www.android-x86.org/documents/installhowto.
Why on your PC?...
This might seem dumb, but it works. Go into preferences, select backup folder location and then hit the back arrow twice. Now you can select the external card. I found this somewhere and don't remember who figured it out, just passing it along.
Very stable on the build I have. Works but a few insignificant tweaks. It could be released as is. Hope the final is close in.
I'm having this problem too. Exactly the same setup as OP, no rooting, no custom recovery stuff, just straight out of the box stock everything, but updated to B309 a couple weeks ago. I downloaded the downgrade, unzipped to dload of root of SDcard...
Have they fixed the main bugs? Launcher not sticking etc?
Launcher does not survive a reboot. You can change to your favorite and it will work until you reboot.