Building Heads

Heads is supposed to be a reproducible build and as of v0.1.0 it achieved this goal. The downside is that the initial build can take a very long time as it downloads and builds all of the its dependencies. One issue right now is that it builds not just one, but two cross compilers and as a result takes about 45 minutes. Luckily subsequent builds only take about 30 seconds to produce a full coreboot and Linux ROM image, but that first ones a doozy…

Heads buils should be fully reproducible on any Linux-ish system (OSX build is not supported). If you don’t get the same hashes as reported on the release page, please file an issue against the reproducible build milestone.

With a vanilla Debian 9 or Ubuntu 16.04 install, such as a digitalocean droplet, you need to first install some support tools. This takes a short while, so get a cup of coffee and install host build requirements packages as specified here

On a Fedora machine, install host build requirements packages as specified here.

For emulation and analysis with UEFITool under Fedora, install qemu and qt5-devel:

dnf install -y qemu qt5-devel

Clone the tree:

git clone https://github.com/osresearch/heads
cd heads

Builds of Heads should be reproducible unless issues are currently known, see Heads milestone #1 for more detail, which means that Heads will build in the exact same way on different computers. Because of this, as a user, you can guarantee that Heads has built correctly and has not been tampered with.

However, this also means that the first time you build Heads it must first build the compilers that it will use to build itself. If that seems complicated, don’t worry. The result is that the first build of Heads will take about an hour to complete. After the first build, building Heads will take less than a minute.

Useful targets, stored under the board directory of the git tree.

Generated roms are generally found under build/$BOARD/$BOARD.rom

Generic

Generally, everything that is needed to flash the SPI flash of a board is a single rom generated through make BOARD=$BOARD command, where $BOARD is the name of the board that can be found under board directory of the git downloaded tree.

Make Heads for another board (XXX should be the name of your board in ./boards and YY the number of CPUs you want to build with):

 make BOARD=XXX CPUS=YY

The resulting rom file will be either ./build/XXX/XXX.rom or ./build/XXX/heads-XXX-vYYYY-gZZZZZZZ.rom (XXX should be the name of your board in ./boards, vYYYY the pinned Heads version and ZZZZZZ the commit id from which your build comes from).

Please continue to the corresponding flashing guide for your device.

More options and detail about Heads modules under Makefile