It appears that the Mibox isn't responding to the remote after you had it off for a few hours. Before the update. I was able to turn it on by pressing the power on the remote. Now it doesn't respond unless I unplug the power and plug it back on to restart the device.
Is this happening with anyone else's Mibox?
This is happening on both of my boxes after the Oreo update. The solution I've found is to hold the Home & Back button to wake it up, as if you're pairing a new remote.