[Samsung Galaxy S9  Questions & Answers] titusct:
Hi there,

after having tried different methods to root my S9, which has updated to Android 10 One UI 2.0 this morning, maybe the solution that finally worked for me will help you too.

First I tried to root just like in Pie, as found on the net: flashed TWRP 3.2.3 via Odin, then flashed Magisk with TWRP plus this no-verity-opt-encrypt. Got stuck in bootloop, tried different no-verity/dm-verity versions, Magisk 18.x and Magisk 20.1. Nothing worked, got stuck again every time i rebootet the system again.

Then, after realising that I CANT get back to Android 9 (old rom wasnt Odin flashable anymore, phone didnt boot, BSoD), I first downloaded the new stock rom and bootloader as zip, got it from here:

https://xdaforums.com/showpost.php?p=81615561&postcount=1830.

You have to check if that fits with your version / phone. Once downloaded, I copied both onto my SD card. So now I was able to install at least the new clean stock rom. Oh, and now I used the

TWRP version 3.3.1.

Then I found this:

https://xdaforums.com/galaxy-s9/development/root-s9plus-exynos-android10-t4065343

At first I tried to root without the SoLdieR9312's mod, only with MAGISK 20.3 and no-verity. Stuck again, it only bootet to download mode, nothing else. So flashed again the clean stock rom, and after first not keeping the right order (I suppose) I finally followed

EXACTLY

the instructions 1 - 4 in above manual including SoLdieR9312's mod (I highly recommend first a complete Wipe, format data, and then flash the clean new Rom with Android 10 and bootloader from above link).

Now, to save you the time I spent today: once your phone is bootet (and succesfully rooted via Magisk 20.3, which will happen automatically due to the SoLdieR9312's mod),

DONT LET MAGISK UPDATE TO VERSION 20.4

!!!! Magisk Manager asks you to update, but when I did update to 20.4, everything fell apart again, it only bootet to download mode.

Now I seem to have it stable and running with 20.3 and the Multi-Disable.android-by@alucard2.zip. I rebootet 5 times so far just for the sake of it, and it works fine and rootet.

If I can be of further help, please let me know. I spent the last 12 hours on this matter, so dont hesitate.

Greetz from me minus a bunch of nerves ;)

PS: After I wrote the above, I deleted the Knox family in the rootet system, and then it collapsed again and, after BSoD, it only rebootet into download mode. I can not exclude the possibility, that this might have been the reason for some system breakdowns before, as I had to re-do the wipe-clean-install-then-root-then-customize worksteps aroung 8 times yesterday before it was stable as it is now. Now I´ll leave Knox on it, though that itches me a bit. But I´m exhausted for now ;)

PPS:

IMPORTANT

when I try to create a PIN or a pattern for the lock screen, phone reboots to SIM card PIN screen and then keeps rebooting and rebooting. It looks like there are some interferences with root and PIN / security. I did NOT create a Samsung account, only a google one, cause in the beginning i suspected it might have been a Sam acct problem (I constantly couldnt log into it on the phone). Turns out that might not have been the case, rather

a prob between root and setting a lock screen security.