Mmmmhhh... pay attention: Kickstart 3.1 expects to have IDE drive attached (even for A500 versions), so it delays a lot before showing the startup screen.
The same issue happened on A1200 version with no HD installed: in KS 3.1 timeout for IDE has been increased to 30s.
So try waiting 30s and check if you see the picture above.
It happened the same to me when installing onto an A600 with no HD.
Cheers,
Luca "OgniX". \8^)
