Martin Michlmayr

SWARM motherboard

Important note: I no longer own an BCM91250A board, so these pages are not out-of-date and no longer updated. They are only provided in the hope that some of the information might be useful.

Debian on the BCM91250A evaluation board

The BCM91250A is an ATX form factor evaluation board from Broadcom based on their SiByte processor family. Specifically, the BCM91250A uses the BCM1250 processor which features two Broadcom SB-1 (SiByte) MIPS64 CPU cores. On this page, I have collected and offer various technical information which I hope is useful in getting Linux (and Debian in particular) running on the BCM1250 evaluation board (which is also known under the name SWARM) and possibly other boards based on the SiByte processor family.

The BCM91250A can function in both big and little endian mode and Linux as well as Debian support both modes of operation. You need a version of CFE, the firmware used by Broadcom's SiByte evaluation boards, which supports the mode you wish to use. Broadcom has kindly provided me with a bi-endian image which supports both modes depending on your hardware setting. You set the mode through a jumper on the board (J1) as explained in the BCM91250A User Manual. Information about installing this bi-endian image of CFE on your board can be found here.

In addition to CFE, which acts as firmware, there is a program which can be used to load Linux. While CFE itself can boot Linux too, SiByl (the SiByte Loader) offers more features, such as the ability to boot from an IDE hard drive and to load an initial ramdisk. SiByl is packaged for Debian. SiByl is used by Debian to offer a full Linux installation to IDE hard drive with the ability to boot from disk.

Getting started

I suggest to start by reading the various bits of information which are available about this evaluation board. Unfortunately, not all of the information has been collected in one place, but instead it is spread around several places. The first document to read is definitely the BCM91250A Evaluation Board User Manual, followed by the CFE manual found in CFE's tar ball.

Technical Information



If you need any help getting Debian running on your BCM91250A after reading this installation guide and using Google, you can contact the Debian MIPS mailing list.

A note for individuals who do not have such an evaluation board yet and wish to have one after reading this page: unfortunately, these boards are not made for end-users and given the low production run they are too expensive for individuals to acquire.