[Android Stick & Console AMLogic based Computers] RBeze58:
Try Method 2 only if you're sure your Remote has no problem and is connected properly. First is trying to determine the course of action. If you just bricked it. Then there's nothing you can do unless you take it to the care center or if you had adb enabled then you can force it into fast boot look after connecting it to your pc. That will be in another post. For now troubleshooting it is our concern.

So you have tried to use the TV Box and you can't force it to go into recovery mode neither have you had any luck with the usb stick update.

Method 1:

The problem is Mi TV Box won't boot and will infinitely boot loop unless the paired remote is connected. So most likely the boot loop is caused as the remote and tv box isn't communicating. Your remote may either be damaged or need a change of batteries or may have been unpaired/disconnected after the update.

So grab a USB mouse or USB Keyboard. Try mouse click and there will be a blank screen. Wait for 5-10 minutes. It takes time to load or is simply slower when disconnected from the remote.

Some keyboards don't work. But if they do, keep pressing either Esc or Enter till the Bootloop ends and brings you to a blank screen. Be patient and use a mouse/keyboard arrow keys to navigate to settings and Remote & Accessories. Then select Xiaomi RC and click on Unpair. The Battery % will be shown if it was connected properly. So then re-pair the remote and then restart. You can restart by holding the power button till the power menu pops up. That's it and that's all. Be careful since both Mi TV and Mi TV Boxes will not make it past the boot screen unless the paired or stock remote is connected properly. You can't find a totally working replacement/spare remote since the remote and the tv box are one unit and if either is damaged or has a manufacturing defect, it can't be easily replaced. As both have sort of link. So suppose you buy two Mi TV 4K Boxes and use both at the same time. The remotes will pair up and be forever linked to one particular at the time of set up. You can't randomly change it after that. Exceptions are always there but this is the case for the most part. Or so I believe it to be.

Method 2: If the above method didn't fix it. The issue is software related. You may need to perform a hard reset using either the recovery or get a keyboard with the same or equivalent combination of keys you'll use on the remote. Considering the remote not working or unable to boot into recovery using the remote. If possible get two people to do the recovery sequence on the remote. Since the remote is good quality and sensitivity for button press. Then load up the stable or latest beta update available onto a pen drive. Make sure that the update package is renamed to update.zip. Before installing Wipe/Reset All Data and it'll ask for confirmation. Confirm it and then proceed to install update.zip. The Pen Drive used may also result in success or failure. So use a reliable know good USB 3.0/2.0 stick. SanDisk gave me issues. I had to re-install thrice to get it to work properly. Also don't use sizes above 16 GB. Upto 32 GB is supported. And it may support external harddisk drives but the format is to be kept in mind. Any pendrive larger than 32 GB comes out of the box with either NTFS or exFAT File System Format. So check that before you put the update on it.