On Tue, 11 Apr 2006, Stefan Reinauer wrote:
- Duncan Laurie dlaurie@google.com [060410 20:13]:
Flash of system BIOS can be done through the service processor as it has hooks into the LPC bus (system must be in reset for this to work). This means a LinuxBIOS port would not be overly dangerous since you can always flash a working BIOS by reloading SP firmware (which includes a system BIOS).
If it works similar to the Sun Fire v20z (newisys 2100e) the flash upgrade mechanism in the SP is pretty useless as it only works when you did not mess up the bios of the machine. What this does is tell the bios: "Please update yourself, here's the data"
This one is different; considerably more invasive but useful. It does not care what (if anything) is currently loaded in the system bios flash and will read and write directly via the LPC bus. Since LPC is no good at sharing this requires the system to be held in reset to guarantee it is idle or all sorts of strange things will happen.
The downside is you cannot do a BIOS upgrade via the SP through an in-band method since you would lose communiation. (tricks could be done to load the image first and flash later but then you lose notification of failures, etc etc) It is still possible to do a direct BIOS flash on the system with the right (DOS) tool.
-duncan