[flashrom] DOS binary doesn't work?

Stefan Reinauer stepan at coreboot.org
Tue Oct 19 19:22:56 CEST 2010


* max <opendtv at yahoo.com> [101012 07:33]:
> --- On Mon, 10/11/10, max <opendtv at yahoo.com> wrote:
> 
> > Thank you, lspci yielded some interesting information. On
> > the linux that works, there are two kernel modules
> > associated with device 8086/24C0 (where the write enable
> > register is located): iTCO_wdt and intel-rng. Those modules
> > are not present on the linux that doesn't work.
> 
> Ok, I have the answer. It was iTCO_wdt, not intel_rng as I first guessed. iTCO_wdt clears bit 13 (TCO_EN) of SMI_EN. This is what allows flashrom to enable writing (tested by clearing the bit with a debugger and running DOS flashrom).
> 
> from iTCO_wdt.c iTCO_wdt_init:
> 	/* Bit 13: TCO_EN -> 0 = Disables TCO logic generating an SMI# */
> 	val32 = inl(SMI_EN);
> 	val32 &= 0xffffdfff;	/* Turn off SMI clearing watchdog */
> 	outl(val32, SMI_EN);
>

Nice finding! Don't you love the effectiveness of SPI flash protection?
:) 

Stefan




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