[OnePlus 3 & 3T Cross Device Development] henk717:
DISCLAIMER

The usual disclaimer with an extra warning, this recovery
WILL automatically modify your phone on first boot.
While this should be an entirely safe modification
it is always possible your phone is in a broken state
either on a software or hardware level causing further problems.
This recovery should under no circumstances be flashed
for the first time on a bricked phone
as the automatic changes might damage it further.
ONLY FLASH THIS ON A PHONE IN GOOD CONDITION!
By flashing this recovery you consent to a vendor partition
being created and to take full personal responsibility of any damage
the usage of this recovery may cause rather than blaming it on me.

ABOUT

This modified TWRP is the recovery image i have been using on my personal OnePlus 3T for the past month, with the increasing popularity of system-as-root roms and the issues this causes for older zip files (Such as Google Apps not flashing with wrong arm version errors) i have decided that it would be worth sharing with the community. This recovery image is a ramdisk modification of the TWRP supplied by the LineageOS Unofficial Treble Port Project (Similar to how SHRP is a ramdisk modification of existing TWRP images). Because this is not a source modification (and neither has TWRP been compiled from source) you can find the original source code in their topic. I hope this recovery will be useful to those who often flash multiple kinds of roms and want one recovery that does it all. It has been tested on the Oxygen OS 4, 5 and 9 firmwares and should have great compatibility with all of them.

Included Features

Automatic Vendor Partition Creation and full Treble support

WARNING: Because this recovery will automatically create the vendor partition it should exclusively be used on devices in good conditions. In the very rare case that bricks occur you can revert the change using the MSMDownloadTool (This can only be used on healthy hardware). If you are unsure about the condition of your device or if your device is currently in a bricked state it is best to use another recovery. I am not responsible for further damage to your phone.

Originally the TWRP image provided by the Treble project needs you to type in the 'treblize' command followed by manual reboots, I have automated this process. From the moment you first boot this recovery the vendor partition will automatically be created and the recovery reboots automatically in a new recovery session (This is not a crash and only happens once). If vendor partition has been detected you will be able to see /treblized as a directory on your phone (This is done in RAM and only visible during your recovery session). The vendor partition does not conflict in any way, you can use and pass safetynet on regular roms at will as it is invisible to a rom using a non treble kernel. Before flashing GSI roms please first flash a proper vendor partiton (This can be done by flashing the LineageOS treble rom the regular way).

/system and /system_root hybrid for maximum compatibility!

This is one of my main reasons for sharing this recovery publicly, i have modified the /etc/fstab file to be able to both mount to /system and to /system_root. This means that older zips that expect /system now work again without breaking compatibility with newer system as root or GSI roms. This is one recovery that can do it all! Inside the root folder you will find a flashable zip called Mount-System.zip. This can be used before incompatible zips to mount the /system partition correctly. This tool will automatically detect system-as-root if present and mount /system to /system_root/system, if not present it mounts /system to /system_root. You should prefer this method over the mounting options found in the menu, these should only be used for unmounting system. Keep in mind that by doing this you are messing around with scenario's the original developers have not foreseen and while flashing these previously broken zips is now possible you cause issues in your ROM. Always flash these previously incompatible zips with care and make a backup first! Do not use this Mount-System.zip to flash new roms, those are best flashed in an unmounted state. The same applies for Magisk and any other system-as-root compatible zips. If you are flashing regular roms my fstab changes will be enough and mount-system will not be needed.

Magisk + Magisk Manager on the ramdisk

In the / directory alongside the other zip files you will find Install-Magisk.zip and Manage-Magisk.zip, these can be used to both install and recovery from Magisk related issues. You no longer need to worry about keeping a copy of Magisk at hand after wiping the data or when you are in need of a downgrade, with this a copy of Magisk and a GUI management tool is always available to you directly from the recovery's root folder.

Persist Backup Tool

It is very important that you keep a spare backup of your persist partition, even the MSMDownloadTool will not be able to repair this as it is unique to your device. In addition devices with persist issues (Sensors, LTE, IMSEI, Wifi, not working / blank) should not use the MSMDownloadTool at all since it can leave you with an unbootable phone. Flash the Backup-Persist.zip file (Found in the recovery's root directory) to automatically create a copy of your persist partition stored on your sdcard so you can easily back this up to a secure location. Persist is even more important than backing up the EFS! An EFS backup alone will NOT recover your phone in the case of persist corruption!

Download

Modified Files

This project contains work from

TWRP Base Image and original Treblize scripts : The Unofficial LineageOS Treble Project

Install-Magisk.zip : Magisk

Manage-Magisk.zip : Magisk Manager Recovery Tool

Known issues

Before uploading i did extensive testing, in some scenario's i managed to cause a hard crash of the recovery image, this is not related to any of the included tweaks but seems to be an issue with flashing a rom when you have just formatted partitions. I advice to always reboot after a partition format or before flashing a system rom to ensure that everything is in a state it can be properly mounted. If you did trigger this white light crash do not fear, your device is not bricked (Unless whatever you flashed bricked it). You should be able to turn it off using the power button after which it will boot up just fine and you can try flashing again.

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