Spansion S25FL128L readout

[Hilco de Lathouder]

Hi All,

I have a Spansion chip I want to read but it seems not supported by 
flashrom. I can connect and read JEDEC ID with BusPirate: it says 
01-60-18 which corresponds with the Spansion S25FL128L (specs available 
online). Flashrom does not detect it. I tried reading it while forcing 
any of the other 128Mbit Spansion chips, but could not make anything of 
the rom with Binwalk.

What would be the best strategy to get to the contents of this chip?

Thanks in advance,

Hilco

[Nico Huber]

Hello Hilco,

On 24.05.22 17:48, Hilco de Lathouder via flashrom wrote:
> I have a Spansion chip I want to read but it seems not supported by
> flashrom. I can connect and read JEDEC ID with BusPirate: it says
> 01-60-18 which corresponds with the Spansion S25FL128L (specs available
> online). Flashrom does not detect it.

I wrote patches to add support[1]. Let me know if you want to test them
and need help to apply patches and build flashrom.
> I tried reading it while forcing
> any of the other 128Mbit Spansion chips, but could not make anything of
> the rom with Binwalk.

However, this should have worked already. Reading works the same for
virtually all SPI NOR flash chips.
> What would be the best strategy to get to the contents of this chip?

First thing to test is if the reading is reliable (flashrom can't tell
because there are no integrity checks on the SPI bus). You can read once
and then immediately run the same command with `-v/--verify` instead of
`-r/--read`. If it doesn't say "VERIFIED", the physical setup is likely
to blame. Common issues are long wires from programmer to flash chip,
we recommend <20cm. If the flash chip is on some kind of mainboard, that
may also cause issues[2].

Nico

[1] https://review.coreboot.org/c/flashrom/+/64747
[2] https://flashrom.org/ISP

[Hilco de Lathouder]

Hi Nico,

Thanks for the quick response and patch. I tested and the chip is now 
correctly recognized.
I read-and-verified and the reading seems to be OK, so it's just that 
the contents are not what I expected. But at least I know the flashrom 
part is OK.

Thanks again,

Hilco

Op 28/05/2022 om 18:40 schreef Nico Huber:
> Hello Hilco,
>
> On 24.05.22 17:48, Hilco de Lathouder via flashrom wrote:
> > I have a Spansion chip I want to read but it seems not supported by
> > flashrom. I can connect and read JEDEC ID with BusPirate: it says
> > 01-60-18 which corresponds with the Spansion S25FL128L (specs available
> > online). Flashrom does not detect it.
>
> I wrote patches to add support[1]. Let me know if you want to test them
> and need help to apply patches and build flashrom.
> > I tried reading it while forcing
> > any of the other 128Mbit Spansion chips, but could not make anything of
> > the rom with Binwalk.
>
> However, this should have worked already. Reading works the same for
> virtually all SPI NOR flash chips.
> > What would be the best strategy to get to the contents of this chip?
>
> First thing to test is if the reading is reliable (flashrom can't tell
> because there are no integrity checks on the SPI bus). You can read once
> and then immediately run the same command with `-v/--verify` instead of
> `-r/--read`. If it doesn't say "VERIFIED", the physical setup is likely
> to blame. Common issues are long wires from programmer to flash chip,
> we recommend <20cm. If the flash chip is on some kind of mainboard, that
> may also cause issues[2].
>
> Nico
>
> [1] https://review.coreboot.org/c/flashrom/+/64747
> [2] https://flashrom.org/ISP