If you do not have component output, that could be a problem. If not, then you will need an HDMI to component converter. The Gang-Hu converter is supported by SB - others here have used other brands, YMMV.
If you have component output and it's not working, I believe the M1 only supports up to 1080i. So, you would need to go into the X1 settings and change the box output to 1080i as the output resolution.