Use my selfboot pack : http://assemblergames.com/forums/showthread.php?t=21735

Look in this page to see if sonic1 has special protections: http://www.bucanero.com.ar/dreamcast/ripdb/5/

And you should be good with it!

My pack will create a NRG image, but you can convert it into a cdi using deamon tool to mount it in a virtual drive then make an image of it using discjuggler.

Any more questions, just ask!

FG