The Asus ROG Phone II (codenamed "ASUS_I001D") is a smartphone from Asus. It was released in September 2019.
First download minimal AOSP android-11 tree:
repo init -u git://github.com/minimal-manifest-twrp/platform_manifest_twrp_aosp.git -b twrp-11
Then add this project to a new local manifest (.repo/local_manifests/<your-file-name.xml>:
<project name="android_device_asus_I001D" path="device/asus/I001D" remote="TeamWin" revision="android-11" />
Now you can sync your source:
repo sync
Finally execute these:
. build/envsetup.sh
lunch omni_I001D-eng
mka bootimage
To test it:
fastboot boot $OUT/boot.img