On Wed, 31 Oct 2012 09:40:02 -0400 "Pupic P." <[email protected]> wrote:
> Hi everyone, > > I have a MacBook Pro (13" mid-2009) who, I think, suffers from a bad > firmware flash : from nowhere, or after an update, it makes 9 beeps when > powered on (3 short, 3 long, 3 short) and nothing else. I have found > references from similar cases when people seemed to have recovered by > rewriting a good firmware with flashrom and buspirate ( > http://ho.ax/tag/firmware/). > On my machine I have : > - a chip labelled MX25L3205DM2I-12G > - buspirate 3.6 (v3b, firmware 5.10) > - flashrom v0.9.6.1-r1620 > - hooked (while the chip still on the motherboard (no power, battery out)) > : pin1->CS, pin2->MISO, pin4->GND, pin5->MOSI, pin6->CLK, pin8->3.3v > > * Pins 3,7 not connected. > * I also tried pins 3,7,8 together with the same result. they need to be connected, in this case they need to be set to a distinct potential (namely vcc), but you should always connect all pins of an IC unless noted otherwise in its datasheet. floating pins are evil. > What I get is flashrom ending with : > Probing for Generic unknown SPI chip (RDID), 0 kB: RDID byte 0 parity > violation. probe_spi_rdid_generic: id1 0x00, id2 0x00 > Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI) on > buspirate_spi. > Probing for Generic unknown SPI chip (REMS), 0 kB: probe_spi_rems: id1 0x0, > id2 0x0 > Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI). > > Any idea why? this means that MISO is always read as low. this can have a number of reasons. one of example is that pin8 is also connected to a number of other components that need more power than the bus pirate (or whatever) can deliver. see also http://flashrom.org/ISP -- Kind regards/Mit freundlichen Grüßen, Stefan Tauner _______________________________________________ flashrom mailing list [email protected] http://www.flashrom.org/mailman/listinfo/flashrom
