thread top ad

Collapse

Announcement

Collapse
No announcement yet.

820-3437 No Serial # showing

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • 820-3437 No Serial # showing

    So i purchased this computer to repair, and it did not come with an SSD and the battery was bad. Well after opening it up I saw one of the antenna connectors was gone as well. So I put in another known good battery, SSD as well as repaired the antenna cable. After getting MacOS installed, the serial number is not displaying. I found a post somewhere about using a program or something to "program " the serial number back into the board. Is this possible? The machine works great now except for the missing serial number. I heard also that you could take it to the Apple store and they could do it but where is the fun in that?

  • #2
    You must upload somewhere the BIOS backup of your board and need the serial number you want to put in.
    Medusa programmer is a MUST HAVE TOOL if you plan to repair Apple machines.

    Comment


    • #3
      Well I will be getting a Medusa programmer then!

      Comment


      • #4
        What about desoldering the SPI chip and using a EEPROM Programmer? Is that more of a hassle?

        Comment


        • #5
          You must fix checksum after serial number is changed.
          Medusa "knows" to do that...

          Comment


          • #6
            So I got the Medusa 2 programmer. It tells me there is no serial number. I have copied the BIOS to the medusa2's internal ROM and hooked it up to my desktop via a TL866 programmer. I saved an unmodified copy of the BIOS to my desktop, opened the BIN file in a hex editor. I imagine I now have to figure out the address line of where the serial number should be. Also, the Medusa told my there is no Fsys. I take it that is bad.

            Comment


            • #7
              Looks like Fsys area issue on your backup.
              Find similar BIOS, copy its Fsys block over your backup.
              Change the serial, flash it on Medusa ROM and write Mac ROM.
              Then use Medusa to fix checksum on Mac board.

              You can also change the serial directly on other known good BIOS and use Medusa to clean ME and fix checksum, once file is written on the Mac board...

              Comment


              • #8
                I got the Fsys issue before I copied the backup. It was found on the initial test on the logic board. Would it be easier if I just copied a known good BIOS from a working computer and change the serial? Does the BIOS have to be from the same year, RAM size, Processor?

                Comment


                • #9
                  I have a bunch of working machines so it wouldn't be an issue to get a BIOS copy. Is there a certain search term I can use to find the location of where the serial number should be in the hex editor?

                  Comment


                  • #10
                    Man this stuff is fun!

                    Comment


                    • #11
                      To only chabge the serial, search for SSN; you can get 2-3 occurencies, until find the correct one.

                      To copy entire Fsys block, it is placed between Fsys and $SVS strings on BIOS.

                      Comment


                      • #12
                        I did a search for SSN and it came up with one hit. Óþꢨ[SSNlÍN.Þÿ~“ÕêÂ… is what it looks like.
                        When I do a search for Fsys I get no hits. same with &SVS. Not sure if I have a something set up correctly in my hex editor. This is a working machine BTW.

                        Comment


                        • #13
                          wait, it found $SVS

                          Comment


                          • #14
                            On original BIOS, you can also search directly for serial number from bottom cover; or showed on About This Mac...

                            Comment


                            • #15
                              Not sure I follow you. I know the serial is on the bottom of the computer and under the battery. the problem is in About this Mac where the serial number should be it says "unavailable". When I used the Medusa on the logic board it tells me there is no serial number. I want to put the serial number that was on the computer originally back onto the logic board.

                              Comment

                              thread bottom ad

                              Collapse
                              Working...
                              X