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DragonFlyBSD Works On EFI Runtime ABI Support, But Still Experimental

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  • #11
    Originally posted by c117152 View Post
    0_o ... There's clips for that... http://www.ebay.com/bhp/soic-test-clip
    NO DUH.
    Issue is that in many many motherboards I've had to save from a bad flash you can't use it, and not because it does not fit.
    The 3.3 v isn't just connected to the SPI chip, but to the rest of the board too so you are also dumping power in the board and your power source might not be enough to power up the chip + whatever else might be attached there too, or there might be some other things connected to the board that is pulling up/down the write protect pin when you power the chip or the board, or whatever else you don't really feel like troubleshooting when you can whip out a hot-air desoldering station and pull the fucker away in 2 min.

    On routers I play with, the clip usually works fine, probably because they are much simpler devices with much simpler boards.

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    • #12
      Originally posted by starshipeleven View Post
      NO DUH.
      Issue is that in many many motherboards I've had to save from a bad flash you can't use it, and not because it does not fit.
      The 3.3 v isn't just connected to the SPI chip, but to the rest of the board too so you are also dumping power in the board and your power source might not be enough to power up the chip + whatever else might be attached there too, or there might be some other things connected to the board that is pulling up/down the write protect pin when you power the chip or the board, or whatever else you don't really feel like troubleshooting when you can whip out a hot-air desoldering station and pull the fucker away in 2 min.

      On routers I play with, the clip usually works fine, probably because they are much simpler devices with much simpler boards.
      I didn't experience such problems on routers or laptop boards. I'm not sure I even understand how leakage is possible seeing how the Vcc\GND target board always has a voltage leveling rectifier diode. That is, the i/o pins can't be breached through Vcc since they won't leak back on the other chips' end while the pickups are rated in kOhm (4.7k or 10k usually) so there's always more resistance then the actual EEPROM's IC...

      I'm guessing your clip is either shorted on some exposed area or the copper broke somewhere and you're not getting enough conductance. Well, this is all assuming your CH304 board is giving off enough power to actually drive the EEPROM... But since you're saying it works fine desoldered I'd have to take your word on it.

      Anyhow, regarding the actual subject, I can see how a softie wouldn't need to deal with any of this stuff but if you're writing EFI r/w code I strongly suggest getting an SPI programmer and testing it works on your target board before executing anything
      Besides, if you're a PC tech, it honestly wouldn't hurt owning a fancy one just to do the occasional BIOS update. Just this last year I saw 4 updates on a single workstation board in response to CVEs (Intel ME got updated twice, TXT was disabled once and SmmRuntime was also disabled later) so having one handy in-case something goes wrong is a must nowadays.

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      • #13
        Originally posted by c117152 View Post
        I didn't experience such problems on routers or laptop boards. I'm not sure I even understand how leakage is possible seeing how the Vcc\GND target board always has a voltage leveling rectifier diode. That is, the i/o pins can't be breached through Vcc since they won't leak back on the other chips' end while the pickups are rated in kOhm (4.7k or 10k usually) so there's always more resistance then the actual EEPROM's IC...
        Yeah I know the theory. What happens in practice is that it does not always work, reasons unknown (probably someone went the cheap way somehow), and I never had the time and patience to find out.

        And I had these issues with fancy SPI flashing hardware too, (DediProg I think) not just on cheapo chinese trinkets.

        Besides, if you're a PC tech, it honestly wouldn't hurt owning a fancy one just to do the occasional BIOS update. Just this last year I saw 4 updates on a single workstation board in response to CVEs (Intel ME got updated twice, TXT was disabled once and SmmRuntime was also disabled later) so having one handy in-case something goes wrong is a must nowadays.
        Yeah, I always had a pro tool handy, although my main customers on that issue are gamers and other not-so-skilled tinkerers. The companies I work for are small so they don't usually use true company-grade hardware (they don't even have an internal IT admin/tech).

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        • #14
          c117152 Also a coreboot dev states he could not access the flash chip in-circuit in a laptop he added support for (from article in the news) https://review.coreboot.org/cgit/cor...c0f5f826118550

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