After the os update in November I was able to get screen mirroring working by rebooting then immediately turning on mirroring. That stopped working about a week ago. I tried the post#24 solution (with reboot) with no luck. Numerous times in fact. The All Share Cast app reduces to an app called FW Update, and despite rebooting after uninstalling the Allshare Cast updates it doesn't help - same old hardware issue error. I even tried forced stopping FW Update with no luck, and reinstalling Allshare Cast and trying the whole uninstall updates process again and again with no success. Now I am having problems with the downloaded Navigator app that says it went into read-only mode. I have done uninstalls/reinstalls/redownload data bases on that app and eventually it fails with the same error. Related to the the os upgrade? I have no idea. I have very little knowledge of the inner workings of Android.
As far as screen mirroring goes, I fiddled with wifi-direct settings and related wifi advanced settings hoping something might happen that would allow screen mirroring to work again. Nearby devices enable/disabled. Wifi networking enabled/disabled. Numerous app uninstalls including avast premium got me nowhere, as did attaching the dongle to another TV (remember, the dongle continues to work great with my Galaxy S4 Mini - its just that I want to use the Note Pro and not the s4 with screen mirroring).
I was very happy with this tablet until the os update came along. The update fixed nothing I was using and broke the stuff I need (screen mirroring.) I suppose I will have to do a factory reset and go through a tedious app restore process. I wish I had some confidence that it would work. My experience with the SM-P900 is turning into a major disappointment. Had this os upgrade occurred within the retailer's return window, this thing would have gone back for a refund. I like my S4 Mini but this Android tablet ordeal is a disaster for me.