I am not aware of a mod available to convert your Novo Rev1 to Rev2, but you could buy the board kit for about $120 and build it yourself. Then swap the boards.
Following recommendations by a few posters (myself included) Graham has been able to squeeze a bit more bass of the Solo SRG and has issued an upgrade to the unit. I am being sent one and following burn-in (about 600 hours) I hope to ship the old and new Solo SRG to the same guys who tested it so they can do a side by side of the two units. I am very optimistic and hope the added bass solves this small issue w/ the Solo SRG's sound. More to come!