Note- if you are on BLN-L22C675 Nougat you can do this easily but if you are on other variants, you need to debrand first as per this guide- https://forum.xda-developers.com/hon...t-bln-t3679402
So what I heard earlier that post China Oreo beta, other regions may not get it (via various unofficial channels and on XDA) its finally here, even though via firmware finder but it gives us a glimpse that beta or stable would be coming soon.
I had given my Honor 6X to my brother 6 months back and was using V10 since then but he came yesterday and I tried to enable VOLTE on that phone but was not working. Even though I debranded my Honor 6X from AL10 to BLN-L22 Indian version very easily (guide in my signature) but somehow I was not able to get VOLTE working. Yesterday I tried all the known methods till 2.30 AM My time but VOLTE was not working and I gave up but today morning again I tried and updated my phone to EMUI 8.0 (already kept one phone for my brother so that if something goes wrong, I will give a new one to him so that he can use atleast as he is leaving today)
As VOLTE was not working and I decided to update to Android 8.0 Indian version, I saw a screenshot in my Honor 6X Oreo update discussion thread and downloaded and flashed via HuRUpdater but failed last night and I recovered back to B340 and then updated to B365.
In this guide, I will provide detailed instruction on how to update your Nougat BLN-L22C675 Indian version of Honor 6X to Oreo. Process is simple and you just need patience while updating and post updating I verified, Jio, Vodafone VOLTE working (seems iDEA would work but no 4G in Delhi/NCR).
- Unlocked bootloader.
HiSuite backup/TWRP backup.
- TWRP for BLN - https://mega.nz/#!bY9hRazT!I9kqA3a9i...R4JAYe6rDQqvdE
- All the Oreo files (downloaded from Firmware finder or below URLs)- you need to put your device as BLN-L22HNC675 and it will show these files under B510 firmware version.
- HwOTA zip from https://mega.nz/#!CXRnEaAb!XYodFoS9C...rexcvYzrwnjfGI given in thread Thanks to @vovan1982
If you have not unlocked your your bootloader, please do so. You can refer this guide if not aware of the method-
Unlocking the bootloader-
- Backup all your data as unlocking the bootloader will reset the device and all your data will be erased.
- On windows machine, go to folder C:\adb or wherever you installed the adb drivers.
- Press shift+right click together and select Open command prompt here (it will be open PowerShell here on Windows 8 and Windows 10 machine)
- Run - adb reboot bootloader (this command may prompt for acceptance of RSA key if not already accepted)
- This will boot the phone into bootloader mode.
- Run - fastboot oem unlock <16 digit unlock code- Put your actual code you obtained from Huawei site > (This step will unlock the bootloader and will erase all your data)
- Phone will restart automatically.
- Once on the system, open the PowerShell or command prompt again in ADB folder (can use the previous instance as well)
- Run -
adb reboot bootloader
- Once in bootloader, Run
fastboot flash recovery twrp-3.1.1-0-berlin.img
- Once done with the flashing the TWRP, Run
Actual Oreo update procedure
- Once you have unlocked the bootloader, and installed TWRP recovery via command
- Download the Oreo firmware given above in download link.
- Download the HWOTA_BLN_Eng.zip from the link given above.
- Unzip the HWOTA_BLN_Eng.zip file and move the extracted content (HWOTA_BLN_Eng folder) to adb folder of your PC.
- Copy the downloaded Oreo firmware to C:\adb\HWOTA_BLN_Eng\HWOTA8_BLN\update\ folder.
- Rename update_data_full_public.zip file to update_data_public.zip and update_full_BLN-L22_channel_in.zip to update_all_hw.zip, do not rename the update.zip.
- Boot to bootloader or fastboot mode. Keep your phone connected with PC.
- Go to C:\adb\HWOTA_BLN_Eng\HWOTA8_BLN folder and run the update_eng.bat file and follow the on screen instructions.
- The update_eng.bat will install the TWRP recovery and boot to TWRP (if not, you can remove USB and press power and volume up key and it will boot to TWRP, connect the USB again)
- You will get prompt for update via SD card or script, select via script
- You will get prompt for change region or change firmware, select change firmware.
- It will automatically copy the content of C:\adb\HWOTA_BLN_Eng\HWOTA8_BLN\update, mainly those 3 zips and it will flash automatically.
- You may see the update.zip file flashed as successful with no error but may see Error result  for other 2 zips, dont worry that is expected.
- Once flashed, it will automatically boot to Oreo without any issue and also it will ask if you want to relock your bootloader or keep this unlocked, this is your wish, I kept it unlocked and will be locked in future updates.
- Your Nougat data may remain the same as it was in my case but I would advise to go with Hisuite backup and TWRP backup.
- If phone unable to boot, flash the stock recovery and make factory reset and boot normally, it should boot fine. (haven't encountered this issue though)
- I did factory reset after booting and verifying to system. Everything was working fine but still I did just to avoid any issue or lag (even though no lags were seen)
About Phone info and VOLTE for Jio and Vodafone. iDEA VOLTE would work as well but there is no 4G in NCR.
Update- anyone having issues with call recorder, turn off Google voice typing and recording will work fine.