[OnePlus 6 ROMs, Kernels, Recoveries, & Other Devel] chrcol:
here

https://forums.oneplus.com/threads/...ficial-oxygen-os-roms-and-ota-updates.835607/

but for me it doesnt work. Please read my post and provide an opinion given I just helped you, thanks.

I suspect it may try to install on the opposite slot as I noticed the other slot becomes corrupt after I run the zip file.

---------- Post added at 05:07 ---------- Previous post was at 04:54 ----------

Its definitely opposite slot as I just got it working.

It seems installing TWRP after it breaks it.

So I was in slot A in TWRP.

Ran the havoc OS zip.

Manually switched to slot B as my TWRP doesnt auto switch.

Deliberately did not reinstall TWRP.

Rebooted

Stock recovery said unable to boot due to android been corrupt and offered choice of factory reset.

I factory reset with the stock recovery option, and let it reboot then havoc OS just booted up.

Ok for someone on a new phone the guide is something like this using latest TWRP.

A nandroid backup probably not needed given the recovery tool. But advised so.

1 - Enable OEM unlock and advanced reboot. (in dev menu)

2 - Reboot into fastmode.

3 - Unlock bootloader 'fastboot oem unlock', this will auto wipe and reboot phone.

4 - OEM Unlock should now be forced enabled as it will be detected unlocked bootlader, reenable MTP USB and advanced reboot.

5 - Enable USB MTP and copy TWRP zip and OOS 9.x zip and havoc OS and GAPPS 9.x zip across.

6 - Reboot into bootloader

7 - Start TWRP 'fastboot boot twrp-3.2.3-1-enchilada.img'

8 - Nandroid backup, if you do this copy it to PC. As this process wiped my internal memory. You will also lose internal memory if have to recover with recovery tool.

If on OOS 8.x like I was then do following step so matches android version of latest havoc OS.

9 - Install OOS zip.

10 - goto reboot screen and switch slots, dont reboot.

11 - install OOS zip again.

12 - reboot system

13 - it should remember your dev menu stuff, if not reconfigure as step 5.

14 - reboot into bootloader

15 - boot twrp again 'fastboot boot twrp-3.2.3-1-enchilada.img'

16 - install havoc os zip, this will goto the opposite slot, do NOT install TWRP zip at this stage.

17 - goto reboot menu, select other slot and reboot system.

18 - stock recovery will popup, choose to do a factory reset and reboot

19 - After the initial boot is done havoc OS seems is fine with TWRP, reboot again into bootloader. Enable advanced reboot inside settings to get this option.

19b - enable file transfer mode on usb and check if all zip files still there, mine got wiped, copy them back across if missing. If you made a nandroid backup thats probably gone also, hence I did say copy to PC.

20 - again boot into TWRP 'fastboot boot twrp-3.2.3-1-enchilada.img'

21 - Install havoc OS zip, now its installed on both slots, if you want manually switch slots and reboot system, when I did this it booted fine.

22 - If you did a test reboot get yourself back into TWRP you know the process by now, otherwise next step is finally install TWRP zip, so no more bootloader into TWRP, havoc OS should now be able to boot with TWRP installed on storage and on both slots.

23 - finally can install gapps, magisk etc.