[OnePlus 3 Guides, News, & Discussion] abhibnl:
For Unlocked Bootloader Devices - Flash at your own risk. Make sure to take a complete internal memory backup before flashing.

Following is a copy-paste from OP Forums

Hey everyone,

We know everyone is excited to finally try the delicious Pie update on the OnePlus 3 and OnePlus 3T. Thanks to the feedback from our beta testers, we are getting closer to launching Android Pie on the OnePlus 3 and 3T.

Now, we would like to invite you to download and try the Community Build available here and continue to help us shaping the stable update. Anyone can try this build, but please have in mind it won’t be available via OTA, you’ll have to download and install it yourself.

Community Beta for OnePlus 3

https://oxygenos.oneplus.net/OnePlus3Oxygen_16_OTA_075_all_1904171151_74affb85cc694452.zip

Community Beta for OnePlus 3T

https://oxygenos.oneplus.net/OnePlus3TOxygen_28_OTA_075_all_1904171149_20a0443ddf734944.zip

Those who download the Community Beta build will get OTA update when the stable build is released.

Changelog

System

Updated system to Android™ 9 Pie™

Brand new UI for Android Pie

Updated Android security patch to 2019.4

Do Not Disturb mode

New Do Not Disturb mode with adjustable settings

New Gaming mode 3.0

Added text notification mode

Added notification for 3rd party calls

Phone

Deep integration with Google Duo

Camera

Integrated Google Lens mode

Instructions for updating to the Community Build

For those on the latest stable version 181206

Preconditions: Boot Loader should be locked

Steps:​

Download the file from the link provided on the forum post

Move the downloaded file to internal storage root folder using the File Manager.

The device can then be updated via two methods.

First method: Local Update

Open Settings -> System update -> Click top right setting icon

Choose Local update

Click on the downloaded file and wait until the device reboots

Second Method: Recovery Update

Turn off the device -> Press power and volume up key simultaneously until the device enters the Fastboot Mode

Navigate to Recovery option using volume and power button -> Choose English -> Install from Internal storage -> Select the downloaded zip file -> Select 'Yes'

Wait until the installation is complete -> Reboot

​

For those who are on the latest Open Beta version 180712

Note: The entire data will be wiped since there will be a version transition from Open beta to the stable version. If you made a OnePlus Switch backup, be sure to make a copy of it before moving forward.

Steps:

Download the file form the link provided on the forum post

Move the downloaded file to internal storage

Device can be updated only via Recovery Update:

Turn off the device -> Press power and volume up key simultaneously until the device enters the Fastboot Mode

Navigate to Recovery option using volume and power button -> Choose English -> Install from Internal storage -> Select the downloaded zip file -> Select 'Yes'

Wait until the installation is complete -> Reboot

​

Thank you once again for all your patience and we can’t wait to get your feedback.

We are one step closer to releasing the Pie for OnePlus 3 / 3T, you can now download and try our community build right now.

Never Settle.

EDIT 1

Procedure that worked for me

So I've managed to install it and as expected, I had to format and delete everything on my internal memory. Here is the procedure I've followed and I'm 100% sure it'll work for others too.

Stuff I did before flashing:

1. Took a complete backup of internal memory.

2. Downloaded ROM + Recovery ( I use Holy Dragon custom twrp) + magisk 18.1 zip to an external OTG drive

My Configuration before flashing:

OOS 5.0.8, Unlocked BL, Magisk and root, Custom Kernel, Custom HolyDragon recovery

Procedure I followed:

1. Boot to recovery.

2. Wipe System, Dalvik, Cache

3. "Format Internal Memory". Please note, I formatted internal memory, not just wiped. This will remove encryption for once which will help the rom boot. It won't boot on encrypted partition with unlocked bootloader on first start up.

4. Flashed ROM zip.

5. Flashed twrp image.

6. Pressed power button for as long as possible until it rebooted again.

7. Pressed volume button before it could reboot so that i can select recovery. This step is important. If you won't do it, your recovery will be replaced with stock one.

8. Flash magisk zip. 18.1

9. Reboot system. It will take 10-15 minutes as it will reencrpt the storage.

10. Profit! Enjoy your new official oos pie on OP3/T.

Some things to note:

1. On first boot, it WILL NEED either mobile data or wifi. It downloaded some update and then installed and proceeded.

2. It will ask for your previous pattern. It didn't work for me so i simply login with my previous Gmail account on 5.0.8 and login successfully.

3. You will need to install magisk manager on first boot. It will show magisk not installed. Don't panic. Simply reboot your device once and it will appear in magisk on second reboot.

EDIT 2:

Community Beta 2 Released 5/6/2019

Hey everyone,

Here is the Community beta 2 for the OnePlus 3 and OnePlus 3T, the update primarily contains bug fixes:

Changelog

Bug fixes

Clock timer and stopwatch interface display is incomplete

Microphone doesn't work when earphones are plugged in

Crash issues with native message app

Community Beta 2 for OnePlus 3

https://oxygenos.oneplus.net/OnePlus3Oxygen_16_OTA_080_all_1905061403_459f9d6e543f4a16.zip

Community Beta 2 for onePlus 3T

https://oxygenos.oneplus.net/OnePlus3TOxygen_28_OTA_080_all_1905061406_f9d7f76f3a5d45da.zip