You can run homebrew on 1.51/1.52, but only through the Illuminati (Lumines) exploit, which is pointless seeing as there's a great 2.00 downgrader which is easy to use already out there.

And you can run homebrew on 3.50 through HEN. (Homebrew ENabler, basically a hack that lets you run homebrew through the XMB)

__________________