You will need git-cinnabar installed and in path. Info: https://github.com/glandium/git-cinnabar#setup

build_dot.sh

git clone https://github.com/mozilla/gecko-dev.git
cd gecko-dev
git remote set-url origin hg::https://hg.mozilla.org/mozilla-unified
git remote update
git remote add dot https://github.com/dothq/browser-ff.git
git remote update
git checkout -b dot dot/master
git checkout master
git merge --no-ff dot
git status
./mach bootstrap
./magic_build.sh
./mach run