[coreboot] Dual SPI Flash

Oliver Schinagl oliver+list at schinagl.nl
Tue Mar 27 00:11:23 CEST 2012

On 03/26/12 22:54, Tadas Slotkus wrote:
> Hi,
> the schematic looks good. Sorry I haven't noticed this thread earlier.
> I don't know what's your mainboard, but I had some problems with mine
> since EFI writes to flash during power up?/down? cycles and doesn't like
> hot switched chip during poweroff. Anyways, better be prepared to use
> external programmer, like „wiggler clone“ in case of everything fails.
> Goodluck,
> Tadas
> (Mrtadis)

Thanks, if people here atleast all agree that its sound, I'll send it 
off to seeed to have it printed.

 From what I understood, SPI is a shared bus, so Chip Select 0/1 should 
allow you to switch between various chips/eeproms.

So even if one's motherboard is completly weird, I guess having 
chipselect on chip 1 first, boot, then while booted swap to 2, flash new 
bios, switch back to 1, shutdown. This should work (I cannot image the 
bios/uefi, constantly writing to the eeprom?

Then when powerd down, move your jumpercap/switch back to the newly 
flashed eeprom and you should be golden. If the new flash is coreboot, 
it shouldn't be a problem anymore, if the new flash is some other 
bios/uefi, then take caution when swapping.

But this is what I suspect, I'm sure there's many more people on this 
list who actually really know what happens ;)


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