[OnePlus 8 Pro  Guides, News, & Discussion] GiveMeAnthony:
Preface:

OnePlus has pushed an incremental rollout to OxygenOS for the OnePlus 8 Pro, 10.5.11 (India / Global) and 10.5.10 (Europe). You can find the changelog issued here.

https://forums.oneplus.com/threads/and-10-5-10-eu-for-the-oneplus-8-pro.1253402/

Many have found that the photochrom filter doesn't work as expected or doesn't work at all after this update, this seems to depend on the region. If you want this feature back, I encourage you to write feedback to OnePlus. There are many great changes in this update and I would love to see them in another update with the photochrom filter restored.

This guide is meant to show you how to restore this filter by downgrading the firmware on your phone, this means you will lose out on the other changes present in the new incremental update, including an Android security update. This is meant to be a temporary solution for those that really love this quirky feature and I don't recommend this guide for most people. Also, if you have root on your phone then this should remove it. Currently, this guide doesn't work for India since there's no downgrade image which brings them to 10.5.8. The infrared camera was disabled for India in version 10.5.9 which is the lowest we can downgrade to at the moment.

WARNING:

Do not proceed with this guide if you lack experience flashing ROMs or have the slightest apprehension about bricking your phone. Be sure to read the guide fully before attempting so that you understand how the procedure works. If you're uncomfortable after reading this, stop and forget about it. Leave feedback to OnePlus and wait for an update. I've only tested this with the global version, but this should work with the other regions as well. That being said, I'm not liable for any damage you cause to your device. STOP if you have a network-branded phone. Proceed at your own RISK!

Phone Backup:

Do not skip this step unless you want to start anew with a wiped device. You can use whatever backup method you wish, but the one I did on my own phone was a OnePlus Switch backup and a Google backup which worked decently well.

I also used Google's Autofill services so that it was easy to sign back into my accounts. You could use any password manager like LastPass just the same, but I think this service works better. You can check if your passwords are saved under Settings > Privacy > Advanced > Autofill services from Google > Passwords.

If you use Two Factor Authentication such as through Authy or Google Authenticator, ensure that you're able to authorize a new device with another such as via another device or SMS.

If you want to use my backup method, follow these basic steps. First, you'll backup with OnePlus Switch.

Open the OnePlus Switch app.

Tap "Backup and Restore".

Select "New Backup".

Check everything that you want backed up, then select "Backup Now".

Once finished, plug your phone into a computer and set the USB mode to "File transfer" under the notification bar. On Windows, you'll see the new device in Explorer. For a Mac, you'll need the Android File Transfer program. https://www.android.com/filetransfer/

Copy /opbackup/MobileBackup to somewhere safe on your computer. It will be wiped from your phone in the next procedures, so this is extremely important.

Next, you'll backup using Google.

Open Settings, then go to System > Backup > Toggle "Backup to Google Drive" on if it hasn't been turned on already.

Tap "Back up now" and wait for it to finish.

Downgrade Flash:

This is scariest part of the procedure since your device will first be wiped with this type of flashing before installing the initial firmware. If the flashing procedure is interrupted, you may not be able to recover. Therefore, please do the following before proceeding to ensure that doesn't happen.

Ensure your device is charged at least 30%, I recommend higher though.

Make sure your device is plugged in while flashing.

Have a charged battery backup on hand in case the power grid goes out.

Check that the firmware image isn't corrupted before flashing (instructions ahead, step 3)

Alright, so now for the procedure:

Check your phone region. Open Settings > About phone, then look at the Build number. It should be something like 10.5.11.IN11XX. The IN11XX will denote your region.

IN11AA for Global

IN11DA for India

IN11BA for Europe

You can also check the Model:

IN2025 for Global

IN2021 for India

IN2023 for Europe

If you have an Indian model, discontinue this guide unless you have some other reason to downgrade. You won't be able to restore photochrom.

Download the appropriate downgrade firmware. There's a OnePlus post that included these firmware image files used for rolling back a developer preview. Here, we're using it to rollback the official stock image to an older version.

Look for "Download links for OnePlus 8 Pro" here: https://forums.oneplus.com/threads/android-11-beta-developer-preview-for-oneplus-8-series.1233995/

You'll have 3 versions:

NA for Global

IN for India

EU for Europe

You should know what your region is from step 1. It's vital that you choose the correct region, so if you're unsure then GO BACK to step 1!

Compute the SHA1 checksum of the downloaded firmware image. This is to check that it hasn't been corrupted, which can happen when you download files or have a faulty drive. Windows has a built-in utility called CertUtil and Macs have one called shasum.

Windows

: Open command prompt (find it by searching "cmd" in the search bar), then enter "CertUtil -hashfile" without quotes followed by a space. Drag the downloaded firmware image onto the prompt, then press enter.

Mac

: Open Terminal from Applications > Utilities. Enter "shasum -a 1" without quotes followed by a space. Drag the downloaded firmware image onto the prompt, then press enter.

You'll see a long string of characters, this is the SHA1 checksum. Compare it with the following value according to your region, ensure it matches EXACTLY. If it doesn't then you have a corrupted image or downloaded the wrong region, please go back and download it again.

Global: 96f8ee55a1b8914317c7e24306bb512733530052

Europe: 74a94d4d0b1676a03ddfd40f85635b0036c5b038

Move the downloaded firmware image onto your device. You can do this by plugging in your phone to the computer then set the USB mode to "File transfer" under the notification bar. On Windows, you'll see the new device in Explorer. For a Mac, you'll need the Android File Transfer program. https://www.android.com/filetransfer/

Make sure your phone is charged at least 30% and plugged in as I warned above.

Open Settings > System > System updates.

Tap the gear cog icon in the top right.

Tap "Local upgrade" and select the package you moved onto the phone in step 4. This will wipe your phone and downgrade. DO NOT unplug or turn off the phone, let it finish the entire process because if you don't then it could brick your phone.

Once the phone boots up, skip through as many prompts as possible since you can set it up later. It will say installing updates during these prompts, don't worry about this, it's normal.

Update to 10.5.10 (Global), 10.5.9 (Europe):

This next step is to get you to the most recent update before photochrom was removed or changed. So hold off on restoring your backup and setting up the device.

Download the previous update that had Photochrom.

https://xdaforums.com/oneplus-8-pro/how-to/oneplus-8-pro-repo-oxygen-os-builds-t4084315

Click the reveal content button under "Signed flashable zips" and then the next reveal content button under the appropriate region. Click the download link for 10.5.10 if your region is Global or India, click the download link for 10.5.9 if your region is Europe.

Check the SHA1 checksum using the instructions in step 3 of the previous section. However, you'll instead be comparing to the following values.

Global: 4a08ebb45aed300e8707aa1dc2cbd07ea69344df

Europe: 1f5b792964312a06eb122f813a33787ccf7d3850

As before, make sure these match exactly with you calculated. If not, you downloaded the wrong file or your download is corrupted. Go back to the post and try to download again. The XDA forum post lists MD5 values which are different than SHA1 so please ignore those.

Move the downloaded firmware image onto your device. You can do this by plugging in your phone to the computer then set the USB mode to "File transfer" under the notification bar. On Windows, you'll see the new device in Explorer. For a Mac, you'll need the Android File Transfer program. https://www.android.com/filetransfer/

Make sure your phone is charged at least 30% and plugged in as I warned above.

Open Settings > System > System updates.

Tap the gear cog icon in the top right.

Tap "Local upgrade" and select the package you moved onto the phone in step 3. This will update your phone just like the typical OTA update.

Restoring from backup:

If you've come this far then it means you've already restored Photochrom. If you wanted a newly wiped phone then you're done. Otherwise, continue on to restore your backup. This goes over restoring using the backup method I used at the beginning of this guide.

Plug your phone into a computer and set the USB mode to "File transfer" under the notification bar. On Windows, you'll see the new device in Explorer. For a Mac, you'll need the Android File Transfer program. https://www.android.com/filetransfer/

Copy the /opbackup/MobileBackup folder you saved before back onto the phone. Make sure it has the same path. If you need to then you can create a new opbackup folder.

Back on the phone, open up the OnePlus Switch app.

Select "Backup and Restore" at the bottom.

Select "Restore Backup".

Select and the restore you moved back onto the phone. If you don't see it, it means you didn't move it onto the correct path. It should be in /opbackup/MobileBackup.

Once the OnePlus Switch app has restored your backup, sign into your Google account from Settings > Accounts > + Add account. You should soon see a finish setting up notification from Google, tap this and continue so that it installed all your apps and restores a bunch of settings.

Once finished, double check through your settings to see if it missed anything. For me it got most settings but some weren't set.

Sign back in to all your apps and authorize your 2FA manager if you have one.

Thank you

I hope this has been helpful to some people out there. I put a lot of effort into this and triple-checked everything, but let me know if anything is confusing. I'd be happy to change anything in this guide to help clarify. Ultimately, I'd like to see either OnePlus push out an official update that restores this or see someone create a Stock + Photochrom ROM that only changes code related to that camera to keep the original functionality.