Well, let me rephrase: Synthetic vision requires an AHRS source to drive the attitude information. I'm not familiar with your Lynx device. If it does not have an AHRS, then I don't think you can expect the synthetic vision to work.
If your Lynx doesn't have an AHRS, then I'm a little confused, because if the iFly wasn't getting any attitude information I'd expect it to default to a straight-and-level presentation that just didn't move when your attitude changed. Since it's upside down, it seems to be getting some information from somewhere. Does it seem to move in correlation with the plane, or is it static or erratic?