I've had the official raspberry pi touchscreen for a couple of months and it worked instantly and perfectly out of the box with my Pi2 - and I just upgraded to a Pi3 and it won't display anything now. I went through the steps on the troubleshooting page apt-get update/upgrade and whatnot and the Pi works fine on another monitor but the touchscreen just displays rainbow lines. Upon power up the screen shows rainbow lines with white background and then switches to black background as the Pi boots up. Nothing else happens. Any ideas? All my connections are secure, and I've confirmed the touchscreen still works on my Pi2.
Okay so I plugged in another touchscreen via the hdmi port while it was still plugged into the touchscreen and turned it on and suddenly it started working. Like it suddenly realized oh hey touchscreen yeah I'm one of those. Now it works fine