[flashrom] Getting inconsistent reads with a Raspberry Pi

[Joerg Albert]

Hi,

On 13.07.2017 23:24, David Hobach wrote:
> Dear all,
>
> I'm trying to read a MX25L3206E and a MX25L6406E in-circuit (laptop) with a Raspberry Pi Rev.1 using a POMONA 5220 SOIC clip.
> flashrom v0.9.9-r1955 on Linux 4.9.35+ (armv6l)
>
> Unfortunately I keep getting images with varying md5sums.
>
> Moreover, when switching between the chips, flashrom always detects the chip it was last connected to (i.e. not the real one) and the MX25L6406E is not correctly detected at all in general (incorrectly detected as some other chip).
>
> If anyone knows those symptoms, I'd love to hear a comment!
>
> All external power sources are disconnected (incl. CMOS battery). The 3v3 of the Pi is used for powering. All 8 Pins were connected (incl. Hold and WP to 3v3).
>
>
had similar symptoms with a T530 a couple of weeks ago. It contains both a 64MBit and a 32MBit SPI Flash connected to the same Southbridge pins except for the chip selects. Turned out that the chip select of the opposite chip was floating (the Southbridge was not powered), so it was partly active. There are no pull-up resistors on CS#. Connecting CS# of the opposite chip to the 3.3V from the RaspberryPi helped in my case.


Regards,

Joerg