[coreboot] [solved] Re: [Flashrom] No EEPROM/flash device found. on Syntax SV266A

[Paul Menzel]

Am Samstag, den 21.03.2009, 19:23 +0100 schrieb Carl-Daniel Hailfinger:
> On 21.03.2009 18:57, Paul Menzel wrote:
> > Am Sonntag, den 22.03.2009, 01:28 +0800 schrieb FENG Yu Ning:
> >   
> >> Paul Menzel wrote:
> >>     
> >>> Right. Removing the sticker sure helps. Atmel AT49F002NT is written on
> >>> the chip, which is supposed to be supported by Flashrom.
> >>>
> >>> test.rom also has not only null written to it, so it seems to be
> >>> working.
> >>>
> >>> What could be done, that the chip is auto-detected?
> >>>
> >>> Anything else I can do?
> >>>       
> >> Since the reported IDs differ from those(id1 = 1Fh, id2 = 08h) in
> >> datasheet of AT49F002NT, I am not sure whether access to the flash is
> >> properly done. Let's do some investigation before going further.
> >>
> >> You may want to take a closer look at test.rom.
> >> * How do the first few bytes look like? Do they look like magic
> >> numbers(0xff00, 0x55aa, ..)?
> >>     
> >
> > What is the correct command for doing this. hexdump first lines look
> > like
> >
> > 0000000 e425 6c2d 3568 6f2d 0129 0000 0200 0000
> >   
> 
> OK, the ID cycle is not working. Basically, if the first two bytes of a
> dump are identical to id1,id2 then id1,id2 are not responses to the ID
> command. Try shorter (down to 10 us) or longer (up to 40 ms) delays in
> probe_jedec.

I did change the following myusec_delay() in probe_jedec() in jedec.c

	/* Older chips may need up to 100 us to respond. The ATMEL 29C020
         * needs 10 ms according to the data sheet.
         */
        myusec_delay(10000);

I tried 10, 100, 1000, 10000 and 40000 (all us) and all produced
identical images (checked with diff).

Can this happen? Or did I do something incorrectly?

> By the way, using "xxd" or "hexdump -C" makes sure the bytes in the
> output are not switched around pairwise.

Thanks for the tip.


Bests,

Paul
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