I am having an awkward problem with my MBPro which i'll try to explain as succinctly as I can: The screen of my MBPro (Early 2011) cracked, leaving me unable to see whatever was happening on the screen (photo below). I plugged in a Toshiba external monitor via HDMI cable and mirrored the display. This way I could see the screen of my MBPro. When my new MBPro arrived, I had the clever idea (sarcasm) to reformat the old MBPro to get a 'clean slate'. I created a backup of Sierra on an external HD and reformatted the machine using CMD+R command (external monitor setup was working fine till this point) Once the reformat was done, I booted the machine pressing Option key to reinstall Sierra but I was not able to get a display on the external monitor. I've tried plugging/unplugging the HDMI cable and CMD+F1 but without any success. I would like to be able to get the display back on the external monitor so I can finish the reinstall. Any advice on how to do this would be appreciated! Thanks.