OpenBIOS
OpenBIOS is a project aiming to provide free and open source implementations of Open Firmware. It is also the name of such an implementation.
Most of the implementations provided by OpenBIOS rely on an additional lower-level firmware for hardware initialization, such as coreboot or Das U-Boot.
Provided implementations
Open Firmware
Not to be confused with the IEEE-1275 specification it implements. Released by the company Firmworks. The principal architect of Open Firmware, Mitch Bradley, is chairman of the Open Firmware Working Group and President & Founder of Firmworks. The OLPC XO-1 laptop uses the Open Firmware implementation.
Smart Firmware
Includes a C to FCode compiler. Made by CodeGen, Inc.
OpenBOOT
Released by Sun Microsystems. Supports the sun4v architecture.
OpenBIOS
Portable and licensed under the GPL. Produced by the OpenBIOS project.
SLOF
Slimline Open Firmware. Produced by IBM.