Category: BIOS

AMD RS780 chipset documentation released, coreboot support upcoming

coreboot logo

Good news for kernel hackers, and especially coreboot developers like me: AMD has released the chipset documentation for the RS780 chipset, including the BIOS Developer's Guide. And these documents are being released freely and openly to the public, no NDAs required, which is great!

Quoting from the original announcement on the coreboot-announce mailing list:

The coreboot community, which includes government organizations, corporations, research labs and individuals from around the world, is very excited to expand on our existing and decade-long collaboration with AMD. This collaboration has, over the years, resulted in the inclusion of coreboot into everything from some of the largest AMD-based supercomputers in the world to some of the smallest embedded systems.

Together with the recent SB700/SB710/SB750 documentation release, the Developer Guide release for the RS780 family of Integrated Chipset/Graphics Processors enables the coreboot community to support any board with AMD chipsets out there, from embedded to enthusiast desktop and high-end server boards.

This new release once again demonstrates AMD's commitment to open standards and software that provides an improved user experience and Total Cost of Ownership for users in every walk of life. One cornerstone of this openness is the availability of documentation without NDA, enabling everyone to contribute.

[...]

Coreboot is open source, so every interested developer or user can modify, tweak and extend it to their heart's content.

An additional benefit of this documentation release is flashrom support for all AMD chipsets which enables users to reflash their BIOS/firmware/coreboot from within Linux and *BSD without rebooting.

Coreboot code for the SB700 and 780 chipset family is already being worked on by Zheng Bao at AMD in his spare time and the coreboot community is happy to work with him on finishing and integrating the code into the official coreboot codebase.

We'd like to thank Sharon Troia at AMD for making these documentation releases possible.

The exact download URLs are listed at http://www.coreboot.org/Datasheets.

Flashrom 0.9 release – Flashing your BIOS from the Unix/Linux command line

I have mentioned the flashrom utility in my blog in the past. This is a small command line tool which allows you to update your BIOS/coreboot/firmware chips without opening the computer and without any special boot procedures.

Yesterday, flashrom 0.9 was finally released. Here's a short passage from the release announcement:

After nine years of development and constant improvement, we have added support for every BIOS flash ROM technology present on x86 mainboards and every flash ROM chip we ever saw in the wild.

Highlights of flashrom include:

  • Parallel, LPC, FWH and SPI flash interfaces.
  • 157 flash chip families and half a dozen variants of each family.
  • Flash chip package agnostic. DIP32, PLCC32, DIP8, SO8/SOIC8, TSOP32, TSOP40 and more have all been verified to work.
  • 75 different chipsets, some with multiple flash controllers.
  • Special mainboard enabling code for dozens of nonstandard mainboards.
  • No physical access needed. root access is sufficient.
  • No bootable floppy disk, bootable CD-ROM or other media needed.
  • No keyboard or monitor needed. Simply reflash remotely via SSH.
  • No instant reboot needed. Reflash your ROM in a running system, verify it, be happy. The new firmware will be present next time you boot.
  • Crossflashing and hotflashing is possible as long as the flash chips are electrically and logically compatible (same protocol). Great for recovery.
  • Scriptability. Reflash a whole pool of identical machines at the same time from the command line. It is recommended to check flashrom output and error codes.
  • Speed. flashrom is much faster than vendor flash tools.
  • Supports Linux, FreeBSD, DragonFly BSD, Solaris, Mac OS X. Please refer to the README for build instructions.

Please note that rewriting your flash chip can be dangerous and flashrom developers make no guarantees whatsoever. That said, many users have successfully replaced proprietary tools such as awdflash, amiflash and afudos with flashrom.

Download: flashrom-0.9.0.tar.gz
SVN: svn co svn://coreboot.org/flashrom/trunk flashrom
Debian: apt-get install flashrom

Do yourself a favor and try flashrom next time you want to upgrade your BIOS. No more floppies or bootable CD-ROMs with DOS/Windows binaries or similar crap. Run flashrom conveniently from the Linux command line, or even via SSH or serial console if you want...

Coreboot hacking: How to solder a PLCC socket on your board

Desoldering station.

When trying to port coreboot (previously LinuxBIOS) to a new mainboard you're often confronted with a big problem: the BIOS/ROM chip on the respective motherboard is soldered onto the board (i.e., not in a socket).

This means that you cannot easily (hot-)swap the chip during development or for recovery purposes. So you basically have exactly one try to flash the ROM chip with a fully working/booting coreboot image. If that goes wrong your board is bricked.

Desoldering the chip

This makes it pretty much impossible to develop a coreboot port for such boards (and soldered-on ROM chips are becoming more and more common, unfortunately).

However, I've recently tried to replace the soldered-on (PLCC) ROM chip on one of my boards with a socket. What sounds pretty scary at first, especially given that I have almost non-existant soldering skills, turned out to be really not that hard. Also, it can be done with relatively cheap and readily available equipment.

I have written a short HOWTO for desoldering chips and soldering on sockets in the coreboot wiki, and also finished a video showing most of the process, which I hope will be helpful for others:

Place the PLCC chip


The video is CC-BY-SA 3.0, music is taken from ccmixter.org and is CC-NC 3.0 licensed. Video editing was done using Kino (which uses ffmpeg2theora for Ogg Theora export).

I also tried to upload the video to Vimeo, but first they told me to install the Flash 10 abomination (and there's no way I will do that). After browsing the help/forum pages a bit I found a traditional, non-flash upload form, but that then tells me that I cannot upload Ogg Theora videos. WTF?

Soldering the socket

The Ogg Theora video support feature request has been open for more that a year. Until that issue is fixed I'll just use other video services, thanks...