Building Firefox OS for Symphony GoFox F15 is pretty straightforward, but requires a few extra steps than a standard Firefox OS build for most other devices. The device dolphin refers to a family of devices powered by Spreadtrum chipsets. So, logically, you would clone the mozilla-b2g/B2G repository and configure a build environment for dolphin.

git clone https://github.com/mozilla-b2g/B2G.git
cd B2G
./config.sh dolphin

The resulting images will result in a device showing a white bootscreen if flashed to a GoFox F15. Why? If you plunge down into this repository, you will find a lot of target devices to build for. scx15_x3542plus is our target device, this denotes our Symphony GoFox F15. However, the device scx15_sp7715ga is selected by default, causing the conflict. To resolve this, just do a little search and replace in the config.sh file.

sed -i 's/scx15_sp7715ga/scx15_x3542/g' config.sh

Now, we are ready to build Firefox OS for GoFox! Make sure to use the v1.4 or v2.1 branch to build, upto writing the blog posts, the other branches failed to boot on GoFox F15 in my experiments.

BRANCH=v1.4 ./config.sh dolphin

And then finally make sure you have something to do while you wait for the very lengthy build process to complete, and issue a build.

./build.sh

And you will have your images (boot.img, recovery.img, system.img, cache.img, userdata.img) ready in out/target/product/scx15_x3542 to be flashed via fastboot