Fist things first if you try this and end up with a brick or your device transforms and tries to take over the world; it's not my fault you messed up not me. So just read all of this thread not just the O.P to, and get out of a bind if you reply with "the thread is too long i wont read it please help" don't expect anything short of "there's a search bar use it"
- You need to download Lineage OS 16 by Xsavi i recommend the build "lineage-16.0-20190914-UNOFFICIAL-judypn(More LG Stuff use this).zip". Put into your external SD
- You need to download a GSI from here https://forum.xda-developers.com/pro...ce-development i personally recommend Havoc OS 2.9 and Resurrection Remix 7.0 download the Arm 64 A/B Variant and what ever recommended Gapps Package is linked.
- Extract the GSI you downloaded and copy the extracted Folder into your external SD.
- Boot into TWRP and check your active Slot in the reboot menu.
- Flash LOS 16 Install -> select the ROM zip -> tick Inject TWRP -> Swipe for install (if you're on a, it will be installed to b, and vice versa).
- Go to and select Reboot Menu -> select your inactive slot -> select recovery and you should reboot into your inactive slot.
- Go to and select Wipe Menu -> Swipe to factory reset
- Select install and navigate to your downloaded GSI -> select install image -> select the GSI image -> select the bubble next to "System Image" -> Swipe to Custom Flash.
- Select the wipe menu -> select advanced wipe -> select the square next to "System" -> select "Repair or Change File System" -> select Resize File System -> Swipe to Resize.
- Install any Gapps and/or Magisk and reboot.
Thanks to: @SGCMarkus @Xsavi