Use the information in this page to create the makefiles for your device and product. Please note, unlike the other pages in this section, the contents here are applicable only when creating an entirely new device type and are intended for company build and product teams only.
Understand Build Layers
The build hierarchy includes the abstraction layers that correspond to the physical makeup of a device. These layers are described in the table below. Each layer relates to the one above it in a one-to-many relationship. For example, an architecture can have more than one board and each board can have more than one product. You may define an element in a given layer as a specialization of an element in the same layer, thus eliminating copying and simplifying maintenance.
|Product||myProduct, myProduct_eu, myProduct_eu_fr, j2, sdk||The product layer defines the feature specification of a shipping product such as the modules to build, locales supported, and the configuration for various locales. In other words, this is the name of the overall product. Product-specific variables are defined in product definition makefiles. A product can inherit from other product definitions, which simplifies maintenance. A common method is to create a base product that contains features that apply for all products, then creating product variants based on that base product. For example, you can have two products that differ only by their radios (CDMA vs GSM) inherit from the same base product that does not define a radio.|
|Board/Device||sardine, trout, goldfish||The device/board layer represents the physical layer of plastic on the device (i.e. the industrial design of the device). For example, North American devices probably include QWERTY keyboards whereas devices sold in France probably include AZERTY keyboards. This layer also represents the bare schematics of a product. These include the peripherals on the board and their configuration. The names used are merely codes for different board/device configurations.|
|Arch||arm, x86, mips, arm64, x86_64, mips64||The architecture layer describes the processor configuration and ABI (Application Binary Interface) running on the board.|
Use Build Variants
When building for a particular product, it's often useful to have minor
variations on what is ultimately the final release build. In a module
definition, the module can specify tags with
which can be one or more values of
If a module doesn't specify a tag (by
tag defaults to
optional. An optional module is installed only if
it is required by product configuration with
These are the currently-defined build variants:
This is the default flavor.
This is the flavor intended to be the final release bits.
The same as
Running userdebug builds in testing helps device developers understand performance and power of in-development releases. To maintain consistency between user and userdebug builds, and to achieve reliable metrics in builds used for debugging, device developers should follow these guidelines:
- userdebug is defined as a user build with root access enabled, except:
- userdebug-only apps that are run only on-demand by the user
- Operations that run only during idle maintenance (on charger / fully
charged), such as using
dex2oatfor background compiles
- Do not have any features that depend on the build type in order to be enabled by default or not. Developers are discouraged from using any form of logging that affects battery life, such as debug logging or heap dumping.
- Any debugging features that are enabled by default in userdebug should be clearly defined and shared with all developers working on the project. Only enable those debugging features on a limited-time basis until the issue is resolved.
Customize the Build with Resource Overlays
The Android build system uses resource overlays to customize
a product at build time. Resource overlays specify resource
files that are applied on top of the defaults. To use resource overlays, modify the project
buildfile to set
PRODUCT_PACKAGE_OVERLAYS to a
path relative to your top-level directory. That path becomes a shadow root searched along with
the current root when the build system searches for resources.
The most commonly customized settings are contained in the file frameworks/base/core/res/res/values/config.xml.
To set up a resource overlay on this file, add the overlay directory to the project buildfile, as follows:
PRODUCT_PACKAGE_OVERLAYS := device/DEVICE_IMPLEMENTER/DEVICE_NAME/overlay
PRODUCT_PACKAGE_OVERLAYS := vendor/VENDOR_NAME/overlay
Then, add an overlay file to the directory, for example:
Any strings or string arrays found in the overlay
config.xml file replace
those found in the original file.
Build a Product
There are many ways to organize the source files for your device. We'll briefly go over how the Nexus 6 implementation was organized as an example, but you can organize your source files and build the way you see fit.
Nexus 6 was implemented with a main device configuration named
shamu. From this device configuration, a product is created with a
product definition makefile that declares product-specific information about
the device such as the name and model. You can view the
device/moto/shamu directory to see how all of this is setup.
Write the Makefiles
The following steps describe how to set up product makefiles in a way similar to that of the Nexus 6 product line:
- Create a
device/<company_name>/<device_name>directory for your product. For example,
device/moto/shamu. This directory will contain source code for your device along with the makefiles to build them.
- Create a
device.mkmakefile that declares the files and modules needed for the device. For an example, see
- Create a product definition makefile to create a specific product based on the device. The
following makefile is taken from
device/moto/shamu/aosp_shamu.mkas an example. Notice the product is inheriting from the
vendor/moto/shamu/device-vendor.mkfiles via the makefile while also declaring the product-specific information such as name, brand, and model.
# Inherit from the common Open Source product configuration $(call inherit-product, $(SRC_TARGET_DIR)/product/aosp_base_telephony.mk) PRODUCT_NAME := aosp_shamu PRODUCT_DEVICE := shamu PRODUCT_BRAND := Android PRODUCT_MODEL := AOSP on Shamu PRODUCT_MANUFACTURER := motorola PRODUCT_RESTRICT_VENDOR_FILES := true $(call inherit-product, device/moto/shamu/device.mk) $(call inherit-product-if-exists, vendor/moto/shamu/device-vendor.mk) PRODUCT_NAME := aosp_shamu PRODUCT_PACKAGES += \ Launcher3
See Product Definition Variables for additional product-specific variables you can add to your makefiles.
- Create an
AndroidProducts.mkfile that points to the product's makefiles. In this example, only the product definition makefile is needed. The example below is from
# # This file should set PRODUCT_MAKEFILES to a list of product makefiles # to expose to the build system. LOCAL_DIR will already be set to # the directory containing this file. # # This file may not rely on the value of any variable other than # LOCAL_DIR; do not use any conditionals, and do not look up the # value of any variable that isn't set in this file or in a file that # it includes. # PRODUCT_MAKEFILES := \ $(LOCAL_DIR)/aosp_shamu.mk
- Create a
BoardConfig.mkmakefile that contains board-specific configurations. For an example, see
- Create a
vendorsetup.shfile to add your product (a "lunch combo") to the build along with a build variant separated by a dash. For example:
- At this point, you can create more product variants based on the same device.
Set Product Definition Variables
Product-specific variables are defined in the product's makefile. Variables maintained in a product definition files include:
|PRODUCT_BRAND||The brand (e.g., carrier) the software is customized for, if any|
List of words like
Name of the industrial design. This is also the board name, and the build system uses it to locate the
|PRODUCT_LOCALES||A space-separated list of two-letter language code, two-letter country code pairs that describe several settings for the user, such as the UI language and time, date and currency formatting. The first locale listed in PRODUCT_LOCALES is used as the product's default locale.||
|PRODUCT_MANUFACTURER||Name of the manufacturer||
|PRODUCT_MODEL||End-user-visible name for the end product|
|PRODUCT_NAME||End-user-visible name for the overall product. Appears in the Settings > About screen.|
|PRODUCT_OTA_PUBLIC_KEYS||List of Over the Air (OTA) public keys for the product|
|PRODUCT_PACKAGES||Lists the APKs and modules to install.||
|PRODUCT_PACKAGE_OVERLAYS||Indicate whether to use default resources or add any product specific overlays||
|PRODUCT_PROPERTY_OVERRIDES||List of system property assignments in the format "key=value"|
Set ANDROID_VENDOR_KEYS to connect over USB
ANDROID_VENDOR_KEYS environment variable enables device
manufacturers to access production builds over
adb. Generate a key
for each release that every device will accept, store those internally (such as at
vendor/oem-name/security/adb/), and then use
ANDROID_VENDOR_KEYS to tell
adb to use these canonical
keys rather than random keys.
ANDROID_VENDOR_KEYS environment variable to
point to the directory containing the generated
adb public and
private keys used for encryption. The private key is stored in file. The public
key is stored in file.pub. The
variable points to a file or directory where the generated key pairs are
This variable is set to a file or directory that contains 2048-bit RSA
authentication key pairs generated with the
adb keygen file command.
These key pairs are in addition to the RSA key pairs generated by the ADB
server. An RSA key pair is needed when you use
adb to connect over
USB for the first time.
You must accept the host computer's RSA key to explicitly grant
adb access to the device. By default key pairs generated by the
ADB server are stored in the following key store directories as
adbkey (private key) and
adbkey.pub (public key):
For file locations, on MacOS, this will likely be:
$HOME/.android. On Windows and Linux, this will be:
%USERPOFILE%\.android. On Windows, RSA authentication keys can
also be in
some cases. When the ADB server needs a key, it first searches the ADB server
key store directory. If no keys are found, it then checks the
ANDROID_VENDOR_KEYS environment variable. If no keys are found,
the local ADB server generates and saves a new key pair in the ADB server key
Note: You can override the default directory
where the ADB server stores RSA keys by setting the
ANDROID_SDK_HOME environment variable. On the device, keys are
stored in the
/data/misc/adb/adb_keys/ file, and new authorized
keys are appended to the same file as you accept them.