Tutorial: Root Shield Android TV (2015; 16GB)

We are rooting the Shield Android TV (2015; 16GB SKU) running Android 8.0 (aka Oreo).  This should work on all builds of Oreo moving forward (see changelog).  Looking for the Shield Android TV (2017; 16GB SKU) tutorial?  Click here.  Looking for the 500GB SKU tutorial?  Click here.