The lowRISC project, based on Cambridge, is aiming to create an entirely open source hardware stack. This includes the SoC as well as the development board.
The design is based around RISC-V, a 64-bit RISC instruction set architecture. It supports GCC, LLVM and Linux, pairing the open source hardware with an open source software stack.
The lowRISC project is run as a non-profit organization. The team is built around a team with experiences from Cambridge University, UC Berkley, Raspberry Pi, Dreamwork, Radioscape, Google, OpenRISC and more.