[Samsung Galaxy Note 9 Questions & Answers] JohnNadeau:
In advance, thanks for all of the prior threads and expert advice on this topic!

In particular, I read this post (21 pages, 201 posts) and gleaned a lot of info, but I'm a bit uncertain of some steps.

In addition, I'm trying to help a friend remotely and am hoping to get some Expert Eyes on this before we embark on this downgrade journey.

Please let me know if there are any steps I'm missing or that should be refined/changed.

Specific Model & OS Information:

Galaxy Note 9 US Unlocked Snapdragon

Model Number: SM-N960UZKAXAA

Model (Settings/About Phone): SM-N960U1

Prior Android 8.1.0 AP/CP N960U1UEU1ARL1

Prior Android 8.1.0 CSC N960U1OYM1ARL1

Current Android 9

Build Number PPR1-180610.011.N9600ZHU1CSB2

Preliminary Questions:

Per this post #171 , is above Build Number Bootloader v1 or v2? Will I be able to install Oreo as outlined below?

Answer: Both Android 8 and Android 9 shown above use Bootloader version 1

Is turning off Software Updates on this Unlocked version SM-N960U1 enough to prevent PIE from being served again?

Answer: No, turning off Software Updates was not enough to stop Pie from coming back.

I had to disable Software update (with a blue icon) (underlying package is com.wssyncmldm)

See steps here to disable Software Update

Downgrade to Oreo Steps:

On PC: Download SamMobile 8.1.0 Firmware 2019-01-13 from https://www.sammobile.com/firmwares/galaxy-note9/SM-N960U1/XAA/

On PC: Download/Install Patched ODIN verB: https://xdaforums.com/android/software/patched-odin-3-13-1-t3762572

On PC: Download/Install Samsung SmartSwitch: https://www.samsung.com/us/support/owners/app/smart-switch

Connect Phone to PC with USB Cable (allow for USB drivers to install)

On PC: Run SmartSwitch and backup all accounts, settings, files, messages, pictures, videos, etc.

note: Un-check any option(s) SmartSwitch to install updates (see post) (very important to do this per IT_Architecht post)

Disconnect Phone from PC

On Phone: Per IT_Architect: Consider Performing a Factory Reset, boot the phone, go through set up but SKIP the WiFi Setup (so it doesn't trigger another PIE Update).

On Phone: Power Down then Remove SIM Card (so it doesn't trigger another PIE Update after installing Oreo?)

On PC: Extract the firmware file downloaded in step #1. You should get 5 files:

AP (System &Recovery)

BL (Bootloader)

CP (Modem / Radio)

CSC_*** (Country / Region / Operator)

HOME_CSC_*** (Country / Region / Operator)

On Phone: Boot Phone into Download Mode: First Power Down your phone. Then, Press+Hold "VolDown+Bixby+Power" release when first Samsung Logo appears. Follow screen directions to place in Download Mode.

Connect Phone to PC with USB Cable:

connect your phone to the PC, preferably using the original USB cable you got with your phone. Odin should detect your device and a BLUE box will show up with the COM port number. (Be sure, the SAMSUNG-drivers are installed on your PC!)

On PC: Run Patched ODIN vB:

Install Firmware without HOME_CSC!!! (this will wipe it clean) (the "HOME_CSC" causes boot loop problems?)

Add each file to it's respective field in Odin v3.13.1.

Use CSC_*** if you want to do a clean flash or HOME_CSC_*** if you want to keep your apps and data.

BUT NOTE AGAIN: do NOT use the HOME_CSC option as it may/will cause boot loop problems

Do NOT tick any extra boxes. The only options to be ticked are F.Reset Time and Auto-Reboot.

Click the start button, wait for Odin to say 'PASS' in a GREEN box.

Once the flash is complete, your phone will reboot, and you can disconnect your phone from the PC.

On Phone: After installation of Oreo, Enable Developer Mode (Settings/AboutPhone/SoftwareInformation: Click Build Number 4 times until Developer Mode is Enabled)

On Phone: Turn off Software Updates (to prevent PIE from updating automatically again): Settings/DeveloperMode/"Auto Update System"=Disabled

On PC: Run Smart Switch, restore everything EXCEPT settings (i.e. old Pie settings won't translate to Oreo properly)?

note: Un-check any option(s) SmartSwitch to install updates (see post) (very important to do this per IT_Architecht post)

[*]Use ADB to disable System Updates: See below "STEPS TO DISABLE SYSTEM UPDATES USING ADB" or post See steps here to disable Software Update

On Phone: Insert SIM Card

STEPS TO DISABLE SYSTEM UPDATES USING ADB:

As mentioned in the other post, there are two System Apps named "Software Update":

1) Software update (with a green icon) (underlying com.sec.android.soagent)

2) Software update (with a blue icon) (underlying com.wssyncmldm)

I only disabled com.wssyncmldm.

I did this on four Note 9 US Unlocked and none have since received the PIE update notice since March 22nd, 2019.

Here are the steps I used:

Installed ADB on Windows 10 Computer: Great Overview Here on ADB

Phone: Settings/DeveloperOptions/USB Debugging: ON

Connect USB Cable (watch for prompts)

Computer: Open a Command Prompt; Type in: c:\adb; adb devices; adb shell

Computer: pm disable-user --user 0 com.wssyncmldm

THAT disables the Second/BLUE "Software Update" (com.wssyncmldm)

Phone: Turn USB Debugging: OFF

Confirm it is Disabled:

Phone: Settings/Apps/Menu/ShowSystemApps,

Scroll Down to Software Updates

Blue should indicate "disabled"

Reboot; Confirm