[flashrom] FAILED: NVIDIA MCP61

[William Speirs]

Thanks for getting back to me.

I restarted my computer -- while holding my breath -- and it booted without
issue.

As for testing the modification to the code, I'd rather not. I'm all for
helping open source, but I cannot risk it on this computer. If I had a
board and another BIOS to play around with, then I'd give it a shot.

Thanks again for all the help...

Bill-

On Wed, Jul 18, 2012 at 9:23 PM, Carl-Daniel Hailfinger <
c-d.hailfinger.devel.2006 at gmx.net> wrote:

> Hi Bill,
>
> glad to hear you could restore by writing the backup.
> Analysis follows.
>
>
> Am 18.07.2012 01:39 schrieb William Speirs:
> > $ flashrom -w M2N_0902.ROM
> > flashrom v0.9.5.2-r1517 on Linux
> > Calibrating delay loop... OK.
> > Found chipset "NVIDIA MCP61". Enabling flash write... OK.
> > Found Winbond flash chip "W39V040C" (512 kB, LPC) at physical address
> > 0xfff80000.
>
> A notoriously troublesome chip. It behaves in a weird way (IMHO not
> really JEDEC-compliant) with the JEDEC Toggle Bit algorithm (minimum 50
> ms time between reads). You may be hitting that problem although we
> tried to add workarounds for it.
>
>
> > Reading old flash chip contents... done.
> > Erasing and writing flash chip... ERASE FAILED at 0x00000000!
> > Expected=0xff, Read=0x4f, failed byte count from 0x00000000-0x0000ffff:
> > 0x10000
> > ERASE FAILED!
>
> This is actually not a failed erase, but a misdetected end-of-erase due
> to the JEDEC Toggle Bit weirdness. The erase succeeds eventually,
> roughly half a second after flashrom complains about erase failure.
>
>
> > Reading current flash chip contents... done. ERASE FAILED at 0x00010000!
> > Expected=0xff, Read=0xdf, failed byte count from 0x00000000-0x0007ffff:
> > 0x652aa
> > ERASE FAILED!
>
> This is actually a failed erase due to a flashrom bug in the chip
> definition. Whole-chip erase is not supported by this chip at all, and
> flashrom should not attempt to use that. The successful erase of the
> first 0x10000 bytes is the longterm (admittedly long-term means roughly
> one second here) effect of the first erase attempt.
>
> > FAILED!
> > Uh oh. Erase/write failed. Checking if anything changed.
> > Your flash chip is in an unknown state.
> >
> >
> > I tried a flashrom -r and compared it to the backup I made and it's
> > different. It is also different from the ROM I tried to install.
> >
> > Any thoughts?
>
> Yes. Please download latest flashrom from svn, edit file jedec.c
> function toggle_ready_jedec_slow() and replace
> toggle_ready_jedec_common(flash, dst, 8 * 1000);
> with
> toggle_ready_jedec_common(flash, dst, 100 * 1000);
>
> In theory, that change should work around the hardware bug you're
> hitting, but to be honest I expect more weirdness to show up instead.
> Still, it would be very helpful if you could test that.
>
> Do you have a way to recover (i.e. another board with a LPC flash chip
> in a socket)? I'm asking because I want to keep the risk low, and while
> the test above should be harmless in itself, more tests might be
> necessary later.
>
> Regards,
> Carl-Daniel
>
> --
> http://www.hailfinger.org/
>
>
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