I also have reproduced this flicker which leads to a total freeze on my Lenovo T450 running Stretch with Intel HD Graphics 5500. It was immediately noticed when rebooting and using the linux-image-4.9.0-4-amd kernel. Once I booted back into the previous kernel (4.9.0-3-amd) the problem went away. I also have a dell laptop that has Intel Graphics HD 520 that I upgraded to the 4.9.0-4-amd kernel and the problem does not seem to affect it. Looks like it might be some incompatibility between the 4.9.0-4 kernel and the intel 5500 graphics?
Thanks Dave
