Rocket M2 XM does not support M2 XM firmware version

the older rockets with the USB port does have a slightly different hardware than newrt rockets.   As we convert to the new ath79 target, which incorporates a newer version of the linux kernel, these images do not necessarily support all flavors of a device.   The ath79 images are targeted for very specific hardware Revs and there has been some debate in the openwrt community if an image should support more than one flavor of the various hardware revisions that exist.  As I recall, there is another forum post on this older Rocket USB hardware, that did come to the conclusion to use one of the ar71xx targeted images to get working.  Not sure if that is the bullet or a special build rocket XM ar71xx.    If the bullet ar71xx image is working then this solves the problem and we don't need to do anything further.  

Note, the hardware is not per say ar71xx or ath79.  Rather, these are just different versions of the linux kernel that describes the hardware differently.  in ar71xx, the hardware is described in 'C' language.  In ath79, the hardware is described by a config file, called the device tree.  The newer linux kernels only need a device tree config file that describes the hardware, and no longer needs to be re-compiled and a new image created for a change in the hardware.

Joe AE6XE