[OnePlus 6T  Questions & Answers] Johndoesmoked:
try this

(BASE STOCK ROM)

OnePlus6TOxygen_41_OTA_063_all_2001032024_215eea3f e7c64e37.zip (BETA4)

whatever the rom requires(10.3.0) however the Q beta 4 works just fine, havent found any real bugs / newer security patches etc.

(CUSTOM ROM)

Latest rom that will work with BASE and TWRP decryption

(latest TWRP )

twrp 3.3.1-31 zip

(Latest)

Magisk Canary . Zip

(Latest)

open_gapps - Q

(Latest)

custom compatible kernel

(Latest)

NanoDroid - with con/fig read alter installation notes

(&)

India_Fake_Partition_Deleter

------------------- EASY-CLEAN-INSTALL (LONG BUT BULLETPROOF) -------------------

!(BACK UP STORAGE / U WILL LOSE DATA ETC.

ALL FILES ABOVE CAN BE SUBSTITUTED FOR ANY "IDEAL" ROM SETUP

CONFIGURATIONS YOU MAY PREFER., THESE ARE MYNE)!

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You only need any custom rom with the required BASE STOCK ROM and compatible TWRP version to decrypt storage, and of course, the latest magisk.

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From dirty or clean system - to - clean flash

in cmd type

fastboot boot twrp.img

Install twrp installer.

Mount all partitions / wipe / advanced / check all boxes & wipe all / format.

- - Reboot twrp - -

Mount all partitions / wipe / advanced / check all boxes & wipe all / format.

Reboot twrp

(DONT BE MOUNTING OR UNMOUNTING ANYTHING MANUALY ANYMORE!)

install OOS(BETA4).zip / TWRP installer

- - reboot recovery - -

install OOS(BETA4).zip / TWRP installer

- - reboot to recovery - -

Copy -

Magisk , TWRP & ROM to internal storage.

Format Data

Flash ROM

Flash TWRP installer

Reboot to recovery

Wipe Dalvik/ART Cache

Wipe Data

Flash Magisk.

Reboot system with your device unplugged to be safe (Device may reboot a couple times)

- - reboot to recovery - -

Copy -

Magisk , TWRP & ROM to internal storage.

Flash ROM

Flash TWRP installer

- - reboot to recovery - -

Flash Magisk

BOOT UP System

- - reboot back to recovery - -

Choose Reboot Option / (CHANGE YOUR SLOT) / Back / Reboot Recovery

Flash Magisk.

Reboot system

SETUP ROM

/////////////////////////////////////\OPTIONAL/\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

- - REBOOT TO RECOVERY - -

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STEP *( .=./ )*

Flash GAPPS

Flash India_Fake_Partition_Deleter

Flash NanoDroid (With prefered pre-configured setup/overlay/apps files placed)

Flash Custom Kernel

Re-Flash Magisk again

Click - WIPE DALVIK & Reboot system right after

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- - REBOOT TO RECOVERY - -

Choose Reboot (CHANGE YOUR SLOT TO THE OPPOSITE SLOT)

- - REBOOT BACK TO RECOVERY - -

REPEAT STEP " *( .=./ )* "

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GAME OVER

1up

THIS is EXTENSIVE but will work for any particular rom setup for a/b devices based on Q

---------- Post added at 10:50 PM ---------- Previous post was at 10:47 PM ----------

just follow install guide download latest linageos and gapps from open gapps. and latest magisk and after flash gapps if you cannot sign into a google account then you need to factory reset both slot in system settings menu and then just reinstall magisk and kernel settings modules etc

---------- Post added at 10:52 PM ---------- Previous post was at 10:50 PM ----------

just switch slots in cmd or via twrp and reboot system and factory reset wipe all via the settings in the booted system, not twrp