This may be unrelated, but my uevm has been freezing too, and that seems to have started after plugging in the hdmi cable again. I've had it running stable for weeks before, without a display connected. There has been some weirdness with the linux framebuffer console on these newer kernels anyway. On pyra hardware you get a black screen, on uevm the image jitters all over the place.
It might be worth checking if the freezes happen without a display driver or with no screen connected.