[Samsung Galaxy Note 8 Questions and Answers] krabman:
I was hoping to get some idea of what wasn't important in the process that led to getting a successful root so I could save a lot of typing but the good Doc hasn't got back on it. There is also the fact that we have only so many testers and the week wait makes it hard to sort things out so I didn't want everyone going off half cocked before we could narrow it down. Anyhow... This is going to be long, sorry about that, don't know how to make it shorter but I will try and be as succinct as possible.

First, up front my phone is a M1 Singapore FD variant purchased on ebay. I did not have OEM unlock and tried flashing a number of firmwares in various ways to see if I could enable it. One of the things I think may have been a problem is I believe you may need to go directly into TWRP from downloader without letting it boot past to avoid getting short circuited on the flash. Get back to that later. At any rate I flashed a half dozen or more firmwares before it became clear from other posts we were dealing with a timer and then I gave up and waited. Where it gets interesting is that in each of those flashes when the phone was in the setup process it downloaded a pack of carrier apps, there was no way I could find to skip that. Except the last time, I was going from the UK firmware to the generic Malaysian firmware which was the last firmware I flashed and everything went as normal except on this last flash the carrier bloat did not pop up during setup. I also got the free gift app which I don't qualify for but had never been present before. All of the last flashes were the whole smash, BL, CSC, AP, and so on. Not sure if it means anything but that is where I was when after a FIVE day wait when I got the OEM unlock button and flashed.

There has been some thinking that Knox may have a part in this and I decided to try that out by flashing a rom directly after completing the TWRP portion of the flash while still in recovery to see if it would make a difference to have it removed before boot.

Lastly sometimes things like this can be fixed by resetting before first boot but at the time the Doc was having me try that no one was having any luck getting back into TWRP directly from the bootloader to reset it before the boot process and resetting after did nothing. There were several resets during my flash to try and get something to take. Most are probably needless, perhaps all, but I did them anyways to try and check as many boxes as possible.

So the process, backup your data before proceeding. I downloaded TWRP, magisk, the rom, verity, and put them on a micro SD card to make flashing easier. I removed both my sims and left them out for the entire flash and first boot. In fact I didn't' put the sims back in until after the first couple times I was in and out of TWRP. From there I followed the instructions on the TWRP thread exactly all the way through to the last step of initialization but from there I DID NOT BOOT into system. I then did a factory reset and flashed magisk, and reset again. Then I installed the rom, and did another factory reset. Then I flashed the stand alone version of magisk once more even thought the rom is pre rooted with it already. Then I factory reset again. At that point I allowed it to boot into system.

Folks should read instructions for the ROM installation but in those instructions it says if the rom boots but does not have working root to reboot into recovery and flash magisk. The rom booted fine but I did not have root and booted back into TWRP and installed it with a caches only wipe and rebooted into system. From there root worked but I soon got a toast saying that magisk busybox needed to be installed and the rom would automatically boot into recovery and flash it. The rom did boot into recovery and flashed it successfully. Thats really about it. Sorry for the length of all that.

A couple last points... TWRP flashes pretty quick in odin so you are going to want to have the up/bixby/power buttons already pressed and held when you hit the start button in odin. Failure to do this means that it will get into the boot process before you can catch it and I think that may very well be the end of the line if you fail to keep it in recovery because either the resets or knox deletion may very well be a factor. I set up odin and had the pointer right over the start box in odin so I could carefully use two hands to hold the buttons and start it without letting go. The last thing, I'm not sure if those resets really mattered but doing them shouldn't hurt anything, you folks can make up your own mind on those.

Good luck gents.