Download Links :
Instructions to Flash-
For users with TWRP Recovery- [No need to wipe internal storage if you have decrypted your device]
1. First flash this Chinese TWRP recovery from here on mega link
2. Now boot to Chinese TWRP recovery and wipe Dalvik/CacheData. No need to wipe internal storage
3. Now flash the leaked ROM zip file but don’t reboot, immediately follow the next step.
4. Flash that Chinese TWRP.img by selecting install img option. [This will stop stock recovery from replacing twrp]
5. Now reboot the phone to recovery again.
[Dont boot the phone to system]
6. Now Flash latest Magisk 14.5(1456).
8. Then flash this force encryption disabler zip file from here.
7. Now reboot the phone. Voila . You have your phone booted into latest oreo without data loss
IF YOU DO NOT HAVE DECRYPTED DEVICE THEN YOU WILL HAVE TO GO TO “WIPE” & SELECT “FORMAT DATA”- THIS WILL WIPE INTERNAL STORAGE!
Method 2 : Sideload Method
1.First you need to flash the stock recovery (You can’t flash the ROM on TWRP recovery).
2. Reboot the phone to stock recovery.
3. Wipe all data (everything).
4. Then Select Install Via ADB option
5. Now Sideload The downloaded zip file.
6. After completing, now reboot the phone.
To sideload the ROM- Move the OOS file to ADB Folder & use command- ” adb sideload oos.zip ”
Credits to XDA user- @HatRiGt