Add CPU microcode/support new CPU for Acer Aspire 5738z?

Discussion in 'BIOS Mods' started by ViRazY, Aug 22, 2020.

  1. ViRazY

    ViRazY MDL Novice

    Oct 27, 2018
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    Hi, I am new to all this BIOS modding and just want to modify the latest Acer Aspire 5738z BIOS to support the Intel Core 2 Duo P9500. From what I understand, only the microcode is missing and I found one that I think should be compatible (correct CPUID, platform matches the current microcodes in the BIOS). However I can't seem to be able to get it working. I first tried it with "cbrom" but that always gave me some "not enough space in BIOS file" error. I then tried to manually put it in with a hex editor but there I get the error "could not find BCP DMI block in BIOS ROM file image." when I try to flash it (phlash in DOS). When I use MCExtractor (command: -repo) after my hex edit, it shows the microcode I put in just fine.
    Any advice?
     
  2. ViRazY

    ViRazY MDL Novice

    Oct 27, 2018
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    Thank you very much. It flashed fine and booted with the old CPU, but still no luck with the new one. I checked the cpuid and it's 0x00010676 (SLB4E). Could it actually be a hardware issue? What happens with the new CPU is it boots, restarts after a few seconds and stays on, but nothing actually happens and it doesn't output anything on the screen. The CPU fan seems to be working though.
     
  3. Lutschpuppe

    Lutschpuppe MDL Member

    Dec 23, 2014
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    Can you check if the microcode was updated? You can make a dump of the installed bios or install AIDA64, look at "motherboard", -> "CPUID", -> "Microcode Update Revision" (i don't know if in some cases will show a false revision because of microcode-updates in the operating system).

    Only presence of suitable microcode is no guarant for function; the manufacturer could also suppress usage of different cpus or chipset doesn't support this cpu. Which cpu is working in your machine?
     
  4. ViRazY

    ViRazY MDL Novice

    Oct 27, 2018
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    Sorry for the late response, I was busy with other stuff the whole week. It says 0xa0e in a fresh Arch Linux installation without microcode updates installed on the OS.
     
  5. Lutschpuppe

    Lutschpuppe MDL Member

    Dec 23, 2014
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    Seems it is using the microcode (your cpu-id 0x0001067a, microcode-revision 0x000a0e) from the modded bios. In my opinion the P9500 will work with this microcode, if you have no engineering sample or pre-production model. So there is another restriction or this cpu is defect.
     
  6. ViRazY

    ViRazY MDL Novice

    Oct 27, 2018
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    Something I noticed while swapping CPUs: When I put the old CPU (Pentium T4300) back in, I forgot to tighten the screw to put it in place, meaning it wasn't actually connected to the board and exactly the same thing happened as with the P9500 (fan turns on for a few seconds, restart, stuck). For me that just seems like the P9500 is broken then and I will just order a new one. Thank you very much for your help so far, I will keep this thread updated.