Which Belkin model? They have funny way of doing their model numbers. Only the Broadcom CPU would be supported by Tomato. You could use DD-WRT.
See DD-WRT webpage for what's inside: »
www.dd-wrt.com/wiki/inde ··· s#BelkinTheir "Play", 'Play Max" "Share" and "Share Max" series requires special build for each model. You cannot use generic RT build as they WILL brick.