On Wednesday 12 August 2015, Patrick 'P. J.' McDermott wrote: > Hi, > > I have a Dell OptiPlex 755 USFF which has an Atmel AT26DF321 SPI flash > chip (which is like an AT25DF321 and has the same device ID except it > doesn't have a HOLD# pin). I've used flashrom to read and write the > same chip on another board by ISP using a BeagleBone Black, 10-cm jumper > cables, a SOIC clip, and an ATX PSU. > > However, flashrom with the same ISP setup fails to probe the chip on the > OptiPlex. I've tried two different known-working BBBs, different > cables, two different Pomona SOIC clips, connecting WP# to 3.3 V, > connecting what would be HOLD# on the AT25 to 3.3 V, and different > spispeed clock frequencies from 1 kHz to 10 MHz. > > I've tried powering the chip (and the rest of the board's 3.3-V rail) > with a 3.3-V line of the ATX PSU, and I've tried instead powering the > whole board with the computer's 12-V PSU. I've also tried running > flashrom while holding down the power button to keep the system in > reset. Following some advice on <http://flashrom.org/ISP> I even tried > removing the DIMMs and CPU. > > Every time I get only bytes of 0xff from the chip, as in the attached > log. In my experience that usually means either the programmer isn't > properly connected to the chip or the programmer uses a different data > voltage than the chip does. But I've checked and rechecked all of the > connections, and I know both the BBB and the AT26DF321 use 3.3-V data > signals. > > Unfortunately there don't seem to be any schematics available for this > board (Dell model number 0HX555, ODM model number HX533 A00, ODM might > be Asustek or MiTAC). This system does have an Intel Management Engine > in the northbridge, but even if that was running I should at least be > able to probe the chip and read its contents. > > Does anyone have any ideas of anything else I could try (short of > desoldering the chip from the board) or about what the problem may be? > > Thanks,
Try installing the SERVICE_MODE jumper - it should disable the management engine. -- Ondrej Zary _______________________________________________ flashrom mailing list [email protected] http://www.flashrom.org/mailman/listinfo/flashrom
