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Correct procedure to disable defective onboard RAM on Lenovo T14 gen 1?

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    Correct procedure to disable defective onboard RAM on Lenovo T14 gen 1?

    Good day,
    In my hands I have a Thinkpad T14 gen 1 (20UD002BIX) showing sporadic BSOD issues caused by failing onboard soldered RAM. I suspect disabling the onboard RAM via a bios mod would do the trick.
    The laptop has already the latest updates as well as latest bios 1.51 as of today.
    I informed myself in an attempt to DIY my way to victory but it left me with more questions than answers. This is not a BIOS request, what I really need is somebody to verify that the following procedure is correct.

    Step 1: grab a bios image:
    - Method 1: from the official website: Downloaded "r1buj82w.exe" from here, run it, selected "extract only" to have the installer extract to a directory. Found a "$0AR1B00.FL1" file within, roughly 17MB big.

    - Method 2: extract a dump from the machine itself. I used Universal BIOS Backup ToolKit 2.0, the created dump file is exactly 16MB big.

    A cursory inspection shows that there are many differences between the FL1 and the dump file. Which one is best to go for in your opinion?

    Step 2: apply the script
    I found a script in this thread, however it's unclear if i should apply it directly to that FL1 file, as in this other post it's said that I need to do a whole bunch of operations on that file before it becomes useful and that was for a different laptop model so I stopped there.

    If I run the script directly to the FL1 file, it performs 22 replacements. If I run it on the dump, it only does 21.

    Step 3: flash the newly create image.
    I didn't find a way to flash the new bios once I (hopefully) have it. The laptop doesn't seem to offer a native way to do it from bios interface. Is Phoenix UEFI Winflash v1.5.66 ok? Also I thought it might be possible to overwrite the FL1 file in the extracted folder and rerun the provided Winuptp64.exe inside that same folder, not sure this would work tho.

    #2
    The extracted file"FL1 needs to be edited to make it 16MB. thats the first step.
    Next you need to copy dmi info +win key from your read dump to this FL1 file.
    Now you need to disable onboard ram.
    The back by universal backup tool is not always reliable. You will need a bios programmer to flash the new file anyway.

    Comment


      #3
      Originally posted by mcplslg123 View Post
      The extracted file"FL1 needs to be edited to make it 16MB. thats the first step.
      Next you need to copy dmi info +win key from your read dump to this FL1 file.
      Now you need to disable onboard ram.
      The back by universal backup tool is not always reliable. You will need a bios programmer to flash the new file anyway.
      Thanks for your reply..
      Ok what software do you recommend to get bios dumps? Also why do you recommend a hardware bios programmer over software for flashing.

      Comment


        #4
        Originally posted by NoRelax View Post

        Thanks for your reply..
        Ok what software do you recommend to get bios dumps? Also why do you recommend a hardware bios programmer over software for flashing.
        What is the motherboard model number, it might be possible to disable the ram by moving some resistors around.
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        Comment


          #5
          Originally posted by SMDFlea View Post

          What is the motherboard model number, it might be possible to disable the ram by moving some resistors around.
          I don't have the expertise nor the tooling to attempt that, I would keep that as a last resort. The motherboard model seems to be just the laptop part number above and the version is 0B98417 WIN.

          Comment


            #6
            Originally posted by NoRelax View Post

            Thanks for your reply..
            Ok what software do you recommend to get bios dumps? Also why do you recommend a hardware bios programmer over software for flashing.
            I dont recommend any software to backup bios. I rely on spi programmer to do that as thats foolproof as long as the spi programmer is good.

            Comment


              #7
              Originally posted by mcplslg123 View Post

              I dont recommend any software to backup bios. I rely on spi programmer to do that as thats foolproof as long as the spi programmer is good.
              When using a programmer, is it even necessary to mess with the FL1? Can't I just dump the bios, apply the script, write it back?

              Comment


                #8
                Originally posted by NoRelax View Post

                When using a programmer, is it even necessary to mess with the FL1? Can't I just dump the bios, apply the script, write it back?
                No not necessary to mess with FL1. Patching the bios does not work on all machines. Post the motherboard model number, it will be silkscreened in white writing somewhere, such as NM-C801, NM-C931
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                Comment


                  #9
                  Originally posted by SMDFlea View Post

                  No not necessary to mess with FL1. Patching the bios does not work on all machines. Post the motherboard model number, it will be silkscreened in white writing somewhere, such as NM-C801, NM-C931
                  Ok, it's NM-C801. It was printed under the heatpipe so i couldn't see it.

                  Comment


                    #10
                    Originally posted by SMDFlea View Post

                    No not necessary to mess with FL1. Patching the bios does not work on all machines. Post the motherboard model number, it will be silkscreened in white writing somewhere, such as NM-C801, NM-C931
                    I managed to get a ch341a programmer. Managed to read a dump of the bios with AsProgrammer v2.1.1. The ram disable script did 24 replacements. The bios chip is a W25Q128JWSQ 2034, the mobo is a NM-C801.
                    I'm ready to pull the trigger but I'd like a confirmation first.

                    Comment


                      #11
                      I did it anyway and got a black screen unfortunately. I then wrote back the original bios dump and the laptop booted correctly again.
                      I'm 100% sure the procedure completed perfectly, asprogrammer didn't give any errors and the modified bios CRC32 matched as expected. So I think the issue is the ram disabler script. Anybody has any idea?
                      At least now I know that i can rely on the backup in case things go south, so i can do more tests with a clear mind now. Will keep posted.

                      Comment


                        #12
                        I was wrong, turns out ANY modification will result in the same exact black screen. I even tried to modify a single byte in a seemingly unused section of the bios and that also resulted in the same blank screen. Anybody knows why?
                        All the tests I did were with battery detached, secureboot disabled, no supervisor password, no bitlocker.

                        That aside, I also wondered if the bcdedit method to blacklist memory pages from within Windows works. So I run a memtest86 again, I narrowed the bad ram zones to a surprisingly few pages and set up everything according to this unbelievably detailed thread on passmark forums:
                        https://forums.passmark.com/memtest8...-address-range

                        It seems to be working, now the laptop can run a full cycle of TestMem5 without failing.

                        Two other methods I found online to do the same thing involve editing the registry (https://learn.microsoft.com/en-us/wi...fa-memory-list) or trying this driver (https://github.com/prsyahmi/BadMemory). I didn't try either tho.

                        Comment


                          #13
                          AMD PSB (or Boot Guard in case of Intel) or BIOS region hash checks are good reasons why changing something somewhere in a BIOS can completely brick the machine. That and just the fact that even changing a single byte somewhere can cause the BIOS to crash depending on what it is.
                          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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