"Another effort that is similar in its role to the PC/AT BIOS-based platform occurred with Open
Firmware (OF) [4] and the Common Hardware Reference Platform (CHRP). CHRP was a set of
common platform designs and hardware specifications meant to allow for interoperable designs
among PowerPC (PowerPC) platform builders. Open Firmware, also known as IEEE-1275 [4],
has issues in that it is an interpreted, stack-based byte-code. Very few programmers are facile
in Forth programming, and it is renowned as being “write-once/understand-never”, and having
poor performance, and non-standard tools. Also, Open Firmware has a device tree essentially
duplicating ACPI static tables. As such, the lack of Forth programmers, prevalence of ACPI,
and the fact that UEFI uses standard tools and works alongside ACPI — versus instead-of — helped spell Open Firmware’s lack of growth. In fact, it is used on SPARC and PowerPC, but it
is unsuitable for high-volume machines and thus prevent it from making the leap from niche
server & workstation markets."
Let's rather look at the reasing of the UEFI developers why they have a different opinion on Open Firmware (page 5 of http://www.uefi.org/sites/default/files/resources/A_Tale_of_...):
"Another effort that is similar in its role to the PC/AT BIOS-based platform occurred with Open Firmware (OF) [4] and the Common Hardware Reference Platform (CHRP). CHRP was a set of common platform designs and hardware specifications meant to allow for interoperable designs among PowerPC (PowerPC) platform builders. Open Firmware, also known as IEEE-1275 [4], has issues in that it is an interpreted, stack-based byte-code. Very few programmers are facile in Forth programming, and it is renowned as being “write-once/understand-never”, and having poor performance, and non-standard tools. Also, Open Firmware has a device tree essentially duplicating ACPI static tables. As such, the lack of Forth programmers, prevalence of ACPI, and the fact that UEFI uses standard tools and works alongside ACPI — versus instead-of — helped spell Open Firmware’s lack of growth. In fact, it is used on SPARC and PowerPC, but it is unsuitable for high-volume machines and thus prevent it from making the leap from niche server & workstation markets."