Corrupted firmware upgrade?

[Android Central Question]

A couple of weeks ago on my Note4 a msg popped up and it wanted to do a firmware update, "Downloading do not turn off". I set the phone down and let it do it's thing. About 45 minutes later, I came back and the same msg was there. I hit the home button a few times and nothing happened. I hit the on off button a few times and nothing. It was frozen. 30 minutes later, I finally had to remove the battery to bring the phone back up. Since then it's been really jacked up. It shuts off intermittently, will reboot on it's own, freezes up, display inaccurate battery %, and other odd behaviors. Sometimes it'll display the original msg re firmware upgrade from above, but just freezes up. Other times, it will display another msg "could not do normal boot" along with several lines of device information and freezes up. I've tried to initiate another firmware update but it doesn't do anything. I'm disabled and the phone is my lifeline. Any suggestions as to how I can remedy my situation? Thanks in advance.

 

[B. Diddy]

Welcome to Android Central! You accidentally booted the phone into Download Mode, aka Odin Mode. This is a special mode that allow you to download a firmware file from your PC when connected via USB, and is typically reached by powering the phone on with Power, Home, and Vol Down pressed simultaneously.

The fact that the phone is doing those other odd things suggests there's either a firmware or hardware problem. Try using Smart Switch to reinstall the firmware: http://www.sammobile.com/forum/showthread.php?t=29914