Mine got stuck in a bootloop the other day the night after the update. I kept power cycling it and it eventually worked again.
All good here! Just clicked on search for update and couple automated reboots and pie was served
The issue that is causing the boot loop is because HDMI CEC is enabled. Disable HDMI CEC before you update, and enable it again after the update is installed.
Why have they not disabled this update???
I do not recommend updating it. Its full of bugs. Some people got stuck in bootloop (solved), I got Chromecast (solved) and Google Assistant (not solved) rendered useless.. It's a bad update.
I really go crazy when people post things that have already been posted hundreds of times without searching before.
Many mibox S's are getting bootlooped due to that update, be careful