How Include OrangeFox in you build

How to Inject OrangeFox Recovery into Your Custom ROM Build (Pixel Devices)

When building custom ROMs for modern Pixel devices (Tensor), integrating a custom recovery like OrangeFox directly into the build process can be tricky.

The Problem: AOSP constraints dictate that BUILDING_VENDOR_BOOT_IMAGE must be true when PRODUCT_BUILD_VENDOR_KERNEL_BOOT_IMAGE is true. Because of this, simply using the standard BOARD_PREBUILT_VENDOR_BOOTIMAGE flag will often conflict or break the build when the system expects to compile vendor_kernel_boot.

The Solution: Instead of rewriting the entire device tree associated with vendor_boot, we allow the AOSP build system (Soong) to compile vendor_boot normally. Then, we inject a custom Make task that overrides the final output recipe. This seamlessly replaces the source-built vendor_boot.img with our prebuilt OrangeFox image right before the target-files and OTA payloads are generated.

Follow these steps to implement the injection method.

Step 1: Download and Place the OrangeFox Image

You do not need to clone the TWRP/OrangeFox device tree. You only need the compiled .img file.

1. Download your compiled OrangeFox recovery image.
2. Place it in a convenient location within your Android source tree. Example path: device/google/OrangeFox/Fox.img

Step 2: Edit BoardConfig

You need to declare the prebuilt image in your device's BoardConfig.mk (or BoardConfig-common.mk).

Add the following line to the file, ensuring the path points to where you saved the image in Step 1:

BOARD_PREBUILT_VENDOR_BOOTIMAGE := $(wildcard device/google/OrangeFox/Fox.img)

Step 3: Create the Override Task

Next, we create the .mk file that will override the build recipe. The AOSP build system automatically includes any .mk files located in device/*/build/tasks/, so you do not need to manually import this file anywhere.

1. Create a new file at: device/google/build/tasks/vendor_boot_prebuilt.mk
2. Add the following code to the file:

# vendor_boot_prebuilt.mk — Use prebuilt vendor_boot.img instead of source-built.
#
# Solution: Override the vendor_boot BUILD RECIPE itself. Task files are
# included after the main Makefile, so this recipe replaces the original 
# mkbootimg recipe. Prerequisites from the original rule are still merged 
# (and built), but the recipe body becomes a simple copy operation.
#
# This way $(INSTALLED_VENDOR_BOOTIMAGE_TARGET) IS the prebuilt from the start,
# and everything downstream (target-files, OTA payload) uses the correct image.

ifdef INSTALLED_VENDOR_BOOTIMAGE_TARGET 

$(INSTALLED_VENDOR_BOOTIMAGE_TARGET): device/google/OrangeFox/Fox.img
 @echo "vendor_boot: using prebuilt device/google/OrangeFox/Fox.img"
 $(hide) cp device/google/OrangeFox/Fox.img $@

endif

(Note: If you placed your OrangeFox image in a different directory, make sure to update the path in this snippet to match).

How it works

1. The build system processes your device tree and compiles the kernel and vendor_boot from source as usual.
2. At the very end of the Make process, it reads device/google/build/tasks/vendor_boot_prebuilt.mk.
3. It sees the override for $(INSTALLED_VENDOR_BOOTIMAGE_TARGET).
4. Instead of packaging the newly compiled vendor_boot, it silently copies your Fox.img over it.
5. The final ROM .zip and OTA payload are generated using the OrangeFox image.