http://wiggum.4amlunch.net/hecnet/ios/ 12.4 and 15.1 images for the 1841 router. Unless the router is maxed on ram I'd say use the 12.4 image. I also have 181x (both 12.4 and 15.1) and 2800 (both 12.4 and 15.1) images if anyone needs those. -brian