Sorry I thought you meant an easy way. You could with a jtag interface, but even then the filesystem would have been modified from normal operation so the image of the firmware you dumped would have a different hash than the stock image. You could extract the filesystem and check the binaries and poke around for thing that shouldn't be there, but all this isn't exactly something the average person could do to see if they were infected. If you have the equipment and expertise definitely. Honestly these companies need to step up their game and just make better products in my opinion. It's not like the technology isn't available.
