[AT&T Samsung Galaxy Note5] droidvoider:
This thread is a tip for Googlers who don't know what to do to fix their Note 5 AT&T phone with the following message:

"An error has occurred while updating the device software. Use the emergency recovery function in the Smart Switch PC Software"

<This screen is Odin Download Mode>

The above error screen is secretly "Download Mode", you do not have to get into Odin Download Mode in order to flash your firmware. If you can't get smart switch to work and you don't know your base band version, like me, then trying all the firmwares until one succeeds might be a solution for you.

Where? <I added links to available firmwares and backups I made>

YOU CAN'T DOWNGRADE FIRMWARE Upgrading reduces the chances you will be able to get rid of AT&T apps + Samsung bloatware someday

Root is not available and the locked bootloader is still locked from release so I wouldn't hold my breath

Warning warning warning you should ask for help from your carrier not me!! Proceed foolishly at your own risk

Edit: Feb 11th, 2017

All of these firmwares are available from XDA Members. PLEASE THANK THEM FOR MAKING THEM!

Samsung/AT&T do not provide these to use!!! NOTICE: I made backup copies for these firmwares but you should get them directly and thank the person who provided them!

(DON'T UPGRADE UNLESS YOU MEAN IT!!!! There's no downgrading from Android 6.01 PHA or higher that I'm aware of, and I'm fairly aware.

OJ1 was taken from XDA Member: JUSMEJOSE on this: THREAD

BACKUP OF: N920AATT2AOJ1_Recovery

OGG was taken from XDA Member: Rolland_K on this: THREAD

N920AUCU1AOGG

PB2 was taken from XDA Member: meraz900 on this: THREAD

N920AUCU2APB2_User_Binary

(I am unsure where I got the backup version of PE6)

PE6 was taken from XDA Member: smxwang on this: THREAD

N920AUCU2BPE6

N920AUCU2BPE6 backup

PK1 was taken from XDA Member: smxwang from this: THREAD

N920AUCS4CPK1

Odin version:

I have used Odin 3.10.6 and 3.12.5 to flash the 6.01 ending in PK1 from the above screen. Either of those odin versions obtained via XDA-developers forum will work.

If you need to retry to flash your firmware with Odin after an error you must reboot. VOLUME DOWN BUTTON + POWER BUTTON + HOME BUTTON. keep holding them, you don't have to unplug it will reboot shortly

Added 02-26-2016 --- PJ1 firmware have a corrupted BL combination file from all known online resources! I recovered param.bin from the damage BL and took the remaining files from PJ1 small ota file

Please give thanks to norbarb for sharing this file when no one could find it and get it direct from norbarb! I couldn't find this file anywhere else and I really needed it for testing, thanks norbarb.

https://xdaforums.com/showpost.php?p=69354814&postcount=8

N920AUCS3CPJ1 firmware (BL file is not Odin flashable if anyone needs me to repack it I might take the time to do that.)

Here's the UP file (found from this forum somewhere this is not my work)

SS-N920AUCU3CPHA-to-S3CPJ1-UP

How to flash unpacked boot.img, recovery.img, sboot.bin and etc:

Unpacked .img, .bin files can be flashed directly using "heimdall flash tool for Linux": https://github.com/Benjamin-Dobell/Heimdall

-- To flash sboon.bin, boot.img, recovery.img and other unpacked firmware files use --> Ubuntu 16.10 with heimdall flash tool for Linux from github. Google how to install dependencies

-- Issues these commands before heimdall. sudo apt-get update, sudo apt-get upgrade, sudo apt-get install build-essential (then read appendix for heimdall readme)

-- Use the frontend for heimdall flash tool for Linux --> sudo apt-get install heimdall-frontend

-- Uncheck auto-reboot, don't boot until all files flashed. I'm uncertain what can happen mixing firmware versions in all cases. download mode is fairly safe, recovery mode sounds risky for data

****** I am collecting all firmware for the AT&T Note 5 up to baseband N920AUCS4CPK1. If you have firmware or update files please list them or I can host send me a pm. ******

I need firmware to create removal tools for customers planning to switch carriers on varying versions. My collection so far is efficient but when I find a way to beat the bootloader I would like my tool to be one step regardless of baseband. While I am still trying to find a competent way to forcibly remove the locked bootloader I am confident I will get there especially with the availability of twrp for almost every other variant along with many great kernels for Android 6.01.

Note: I have no idea how to remove the bootloader without access to dirtycow and I haven't confirmed my fix on baseband beyond N920AUCS4CPK1. I would need help from someone very confident with android to test scope beyond baseband N920AUCS4CPK1