These are personal test builds of mine. In no way do I hold responsibility if it/you messes up your device. Proceed at your own risk.

Setup repo tool from here https://source.android.com/setup/develop#installing-repo

Sync TWRP manifest:

repo init --depth=1 -u https://github.com/minimal-manifest-twrp/platform_manifest_twrp_aosp.git -b twrp-11

Make a directory named local_manifest under .repo, and create a new manifest file, for example local_manifests.xml and then paste the following

<?xml version="1.0" encoding="UTF-8"?>
<manifest>
<remote name="github"
	fetch="https://github.com/" />

<project path="device/oneplus/kebab"
	name="theincognito/android_device_oneplus_kebab"
	remote="github"
	revision="android-11" />
</manifest>

You might need to pick few patches from gerrit.twrp.me to get some stuff working.

Sync the sources with

repo sync -j$(nproc --all)

To build, execute these commands in order

. build/envsetup.sh; export ALLOW_MISSING_DEPENDENCIES=true; export LC_ALL=C; lunch twrp_kebab-eng; make -j$(nproc --all) adbd recoveryimage

To test it:

# To temporarily boot it
fastboot boot out/target/product/kebab/recovery.img 

# Since 8T has a separate recovery partition, you can flash the recovery with
fastboot flash recovery recovery.img

Kernel: https://github.com/LineageOS/android_kernel_oneplus_sm8250

• bigbiff for decryption
• Systemad for original tree
• CaptainThrowback for original tree
• mauronofrio for original tree
• TWRP team