Develop Android kernels

This page describes how to develop Android kernels on Cuttlefish devices.

Supported kernel manifests

Cuttlefish supports the following kernel manifests on main and AOSP GSI releases.

• On aosp-main
  • common-android14-6.1
  • common-android14-5.15
  • common-android-mainline
• On aosp-android13-gsi
  • common-android13-5.15
  • common-android13-5.10
• On aosp-android12-gsi
  • common-android12-5.10
  • common-android12-5.4
  • common-android-4.19-stable
• On aosp-android11-gsi
  • common-android11-5.4
  • common-android-4.19-stable
  • common-android-4.14-stable

The following are kernel sources for kernel development on Cuttlefish devices.

• kernel/common-android14-6.1
• kernel/common-android14-5.15
• kernel/common-android13-5.15
• kernel/common-android13-5.10
• kernel/common-android-mainline

Develop Android kernels

To develop kernels on Cuttlefish devices, follow these steps:

1. Clone the appropriate kernel repo manifest for your Cuttlefish device and make any changes.

   mkdir common-android14-6.1
   cd common-android14-6.1
   repo init -u https://android.googlesource.com/kernel/manifest -b common-android14-6.1
   repo sync -c -j$(nproc) -q
   

2. Build the kernel and ramdisk. For more information, see Building the Vendor Modules for the Virtual Device.

   tools/bazel run //common-modules/virtual-device:virtual_device_x86_64_dist
   

   If using common-android-4.19-stable, common-android-4.14-stable, or common-android11-5.4 kernel manifests, run:

   BUILD_CONFIG=common/build.config.gki.x86_64 build/build.sh && BUILD_CONFIG=common-modules/virtual-device/build.config.cuttlefish.x86_64 build/build.sh
   

   Instead of building locally (to avoid downloading the kernel source, setting up a kernel development environment), you can download the relevant artifacts at ci.android.com.

   • android11-5.4
   • android12-5.4
   • android12-5.10
   • android13-5.10
   • android13-5.15
   • android14-5.15
   • android14-6.1
   • android-mainline

3. Launch the kernel and ramdisk with Cuttlefish.

   cvd start \
       -kernel_path=/$PATH/$TO/common-android14-6.1/out/android14-6.1/dist/bzImage \
       -initramfs_path=/$PATH/$TO/common-android14-6.1/out/android14-6.1/dist/initramfs.img
   

   If launching a non-GKI kernel (anything at or under 4.19), omit the -initramfs_path argument.

   If you're launching the kernel on an aarch64 version of Cuttlefish, use the aarch64 build configuration and use the Image artifact instead of bzImage.

   cvd start \
       -kernel_path=/$PATH/$TO/common-android14-6.1/out/android14-5.15/dist/Image \
       -initramfs_path=/$PATH/$TO/common-android14-6.1/out/android14-5.15/dist/initramfs.img