[LinuxBIOS] Unlocking MCP61?

[Arno Willig]

Peter Stuge wrote:
>> I am trying to unlock the MCP61 chipset, any hints how to start?
>> How did you find the unlock sequence for MCP55?
>>     
>
> I believe Yinghai Lu had access to NVIDIA data sheets while working
> for AMD and after having written the code he was eventually allowed
> to release it back to LinuxBIOS.
>  
>> I need to get bios flashing working on a ASUS M2N-MX board using
>> Linux.
>>     
>
> May be much easier said than done. ASUS boards usually do some
> special tricks..
>
>  
>> The sequences for CK804 and MCP55 work for *reading* the bios, but
>> I am not able to write to the chip...
>>     
>
> The flash chip can always be read, for doing anything else you will
> need write access at the hardware layer however.
>
> Does flashrom correctly identify your flash chip? If so, write access
> is in fact working.
Hi Peter!

Yes, identification works correctly (I have three ASUS M2M-MX with 
different bios chips and all of them are identified correctly.
But the erase sequence does not work, debugging toggle_ready_jedec show 
me that there is no toggling at all. :-(

I tried to disassmble the afudos.exe dos tool to get some information 
about additional unlocking. (For educational purposes only, of course :-)
This dos tool seems to call the bios directly by an interrupt, to unlock 
the chip. This interrupt is called once before writing and once after 
writing.
It also seems to be responsible for turning the keyboard off while 
flashing.
Of course this realmode stuff is of no use under linux.

Ciao, Arno