• quaff@lemmy.ca
    link
    fedilink
    English
    arrow-up
    3
    ·
    5 months ago

    I’m running up against the wall of breaking the signature. I guess my motherboard protects itself from unsigned modifications and idiot tinkerers 😂

    • 7heo@lemmy.ml
      link
      fedilink
      English
      arrow-up
      4
      ·
      edit-2
      5 months ago

      You might be able to drop the manufacturer’s keys somehow[1] but I would not recommend.

      If you still really want to do this, I would advise you to:

      1. Unsolder the eeprom
      2. Solder a slot-in socket instead
      3. Get a new blank chip
      4. Get an eeprom programmer
      5. Dump the eeprom to a bin file
      6. Flash that bin file onto the new eeprom
      7. Test that the motherboard POSTs
      8. Search for cryptographic signatures (possibly compressed, possibly obfuscated - rolling XOR, reversed, etc) in the bin file
      9. Hack around that bin file trying to blank the keys, or better yet, replace them with yours.
      10. Go to step 7, repeat.

      Of course, you could always flash the modified bin onto the new eeprom directly at step 6, but what’s the fun in that? 😅

      Also, if you really do this(!), please don’t forget to document. 🙏


      1. I doubt they went as far as “fusing” them in the factory, it would be perceived as “overkill” for a general public product - which I assume it is - and would run the risk of bricking upgradibility of the board, should the manufacturer lose the keys. Plus, it doesn’t help anything (quite the contrary) if the keys are somehow leaked by the manufacturer. ↩︎

      • quaff@lemmy.ca
        link
        fedilink
        English
        arrow-up
        3
        ·
        edit-2
        5 months ago

        Welp. My skills end at #1. So I guess I’m SOL 😂 Thanks for this though! I like knowing that it’s possible, even if it’s outside of my current ability 🙂

        • 7heo@lemmy.ml
          link
          fedilink
          English
          arrow-up
          3
          ·
          edit-2
          5 months ago

          Well, technically, if you can do #1, you can probably do #2… 😋

          And then the rest doesn’t require advanced skills, with the exceptions of point #8. Using a programmer is essentially the same as with any other tool. There is a method, you follow it, and you never, ever get close to the blade with your hands when the machine is running. Oh, no, wait, that is for a different tool. 🙃

          • quaff@lemmy.ca
            link
            fedilink
            English
            arrow-up
            3
            ·
            5 months ago

            For sure haha I meant I don’t have soldering skills. I know there’s a hardware BIOS programmer device I could get, but I feel like at that point, I may as well get a new motherboard 👀

            • BeardedGingerWonder@feddit.uk
              link
              fedilink
              English
              arrow-up
              2
              ·
              5 months ago

              If you’re getting a new motherboard anyway you might as well give it a go. There are some micro soldering training kits you can pick up for ~£15 to practice.