Building for devices

This page complements the main page about Building with information that is specific to individual devices.

The only supported device is Nexus S, a.k.a. "crespo". Nexus S is the recommended device to use with the Android Open-Source Project. Nexus One a.k.a. "passion" is experimentatal and unsupported. Android Developer Phones (ADP1 and ADP2, a.k.a. "dream" and "sapphire") are obsolete, were experimental and unsupported in froyo, and can't be used with gingerbread.

Building fastboot and adb

If you don't already have those tools, fastboot and adb can be built with the regular build system. Follow the instructions on the page about building, and replace the main make command with

$ make fastboot adb

Booting into fastboot mode

During a cold boot, the following key combinations can be used to boot into fastboot mode, which is a mode in the bootloader that can be used to flash the devices:

DeviceKeys
crespoPress and hold Volume Up, then press and hold Power
passionPress and hold the trackball, then press Power
sapphirePress and hold Back, then press Power
dreamPress and hold Back, then press Power

Also, on devices running froyo or later where adb is enabled, the command adb reboot bootloader can be used to reboot from Android directly into the bootloader with no key combinations.

Unlocking the bootloader

It's only possible to flash a custom system if the bootloader allows it.

This is the default setup on ADP1 and ADP2.

On Nexus One and Nexus S, the bootloader is locked by default. With the device in fastboot mode, the bootloader is unlocked with

$ fastboot oem unlock

The procedure must be confirmed on-screen, and deletes the user data for privacy reasons. It only needs to be run once.

On Nexus One, the operation voids the warranty and is irreversible.

On Nexus S, the bootloader can be locked back with

$ fastboot oem lock

Obtaining proprietary drivers

While it's possible to build and run a system using exclusively source code from Android Open-Source Project, such a system can only use the devices' hardware capabilities for which Open-Source drivers exist.

Official drivers for Nexus S can be downloaded from Google's Nexus driver page, which add access to additional hardware capabilities with non-Open-Source drivers.

There are no official drivers for Nexus One, ADP2 or ADP1.

Each driver comes as a self-extracting script in a compressed archive. After uncompressing each archive, run the included self-extracting script from the root of the source tree, confirm that you agree to the terms of the enclosed license agreement, and the drivers and their matching makefiles will get installed in the vendor/ hierarchy of the source tree.

In order to make sure that the newly installed drivers are properly taken into account after being extracted, the existing output of any previous build needs to be deleted with

$ make clobber

Picking and building the configuration that matches a device

The steps to configure and build the Android Open-Source Project are described in the page about Building.

The recommended builds for the various devices are available through the lunch menu, accesed when running the lunch command with no arguments:

DeviceBuild configuration
crespofull_crespo-userdebug
passionfull_passion-userdebug
sapphirefull_sapphire-userdebug
dreamfull_dream-userdebug

Flashing a device

Set the device in fastboot mode if necessary (see above).

Because user data is typically incompatible between builds of Android, it's typically better to delete it when flashing a new system.

$ fastboot erase cache
$ fastboot erase userdata

An entire Android system can be flashed in a single command: this writes teh boot, recovery and system partitions together after verifying that the system bring flashed is compatible with the installed bootloader and radio, and reboots the system.

$ fastboot flashall

On crespo, sapphire and dream (but not on passion), the commands above can be replaced with a single command

$ fastboot -w flashall

Nexus S Bootloader and Cell Radio compatibility

On Nexus S, each version of Android has only been thoroughly tested with on specific version of the underlying bootloader and cell radio software. However, no compatibility issues are expected when running newer systems with older bootloaders and radio images according to the following table:

Android VersionPreferred BootloaderPreferred RadioAlso possible
2.3 to 2.3.2I9020XXJK1I9020XXJK8
2.3.3I9020XXKA3I9020XXKB1versions from 2.3

If you're building a new version of Android, if your Nexus S has an older bootloader and radio image that is marked as being also possible in the table above but is not recognized by the build system, you can locally delete the version-bootloader and version-baseband lines in device/samsung/crespo/board-info.txt