[LinuxBIOS] flashrom support for AMD CS5536

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Tue Nov 27 19:29:17 CET 2007

On 27.11.2007 19:15, Darmawan Salihun wrote:
> Alan Alexander wrote:
>> So, my conclusion is that the actual BIOS settings must be stored
>> elsewhere. I suspect that this is probably obvious to you guys.
> The BIOS setting is stored in a Non-Volatile RAM, known as
> the CMOS chip. (actually it's better to call it NVRAM but
> most people call it the CMOS chip). This chip is battery
> backed, i.e. powered by battery. You can see the battery in
> the board in all likelihood ;-) (Its shape is round, IIRC
> it's a Li-Ion battery). The CMOS contents are accessed
> through I/O port 70h,71h, and in some chipset also through
> 72h and 73h.

There are also BIOS flash chips which have an additional 4kB for
parameter storage. This 4kB segment can NOT be accessed in the usual
way. It also is not affected if you erase or write to the chip.


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