There is an Open Archos forum which has created a Froyo build. It is not for the faint of heart. You are losing multiple functionality to attempt this community firmware. Give it time. They are still in the Alpha stage. The firmware installed is very full featured, and serves the needs if you are wanting an Android PMP. The purpose of a .5 Tb drive is to make it a PMP. Android recognizes the storage, but really designed for those of us who have come from the PMP mode. It does a great job of this. But do not plan it to be a 2.2 build. While it can do that. Archos is putting no effort into that. and it is an end of life Tablet. Similar to the Archos 7HT, These have a limited purpose.
The Archos A5/32 and the A5 phone are very impressive and would be the A5 I would consider if wanting a phone size tablet.