C2758 - What is BIOS POST code 42

  • I have a C2758, which is nearly 3 years old…well, I did before it crashed (ironically, it happened just hours after I ordered a XG-1541 to finally set up redundancy for my home office).
    After figuring out it was a hardware issue, I watched the boot process.  It gets stuck at BIOS POST code 42.

    I could not find an authoritative reference for POST code 42 (although one source said it is the answer to life, the universe, and everything). I did not see a Supermicro-provided list of codes, nothing in the motherboard manual, and the random internet searches had multiple possible error codes depending on the BIOS version (which wasn't helpful when it gets stuck before I can see the BIOS version).

    I am hoping to determine whether I purchase a new motherboard (The included MB is a Supermicro A1SRi-2758F, which is readily available from retailers), new RAM, or if there is a different failed part, as I'd like to keep it around for redundancy.

    Thanks for your assistance!

  • Galactic Empire

    IIRC something to do with the drive you're using.

  • Thanks - it looks like that could be it, but just for the sake the the thread, the issue could not be entirely isolated to the HD, and may [also?] be something else

    After additional troubleshooting, which included switching RAM chip slots (same chips, swapped slots), and a replacement SATA HD [using the existing power/SATA cables], I was able to get it to the BIOS setup screen, change IPMI settings, and install a clean install from an IPMI virtual CD: pfSense-CE-2.3.3-RELEASE-amd64.iso

    The reason I am not certain that the HD is the [only] cause, is that after switching the HD, I was able to view the BIOS system event logs, and there were 20 low CMOS battery alerts.

    1 1970/01/01 00:01:34 VBAT Voltage Lower Critical - Going Low - Asserted
    2 1970/01/01 00:01:34 VBAT Voltage Lower Non-Recoverable - Going Low - Asserted

    19 1970/01/01 00:31:22 VBAT Voltage Lower Critical - Going Low - Asserted
    20 1970/01/01 00:31:22 VBAT Voltage Lower Non-Recoverable - Going Low - Asserted

    [the 1970 dates usually indicate that CMOS lost its date/time when AC power was removed]

    I replaced the CMOS battery (first testing the new battery, which measured 3.3 v)  and rebooted several times (via IPMI). The VBAT remained reading 1.68 v.  At one point it briefly read "within range", but by the time I could see the voltage measurement (on a different IPMI web page), the reading was 1.68 v.

    For the sake of isolating the cause, I plugged back in the original HD (which was the 80 GB Intel SSD that originally came with the server), and got Post code 42 again… so there does seem to be an error with the original drive, but there may also be another issue related to BIOS/CMOS/Battery.

    Since there may be an issue with the MB, it looks like the best option will be to replace the MB, too.

  • @pvuchetich Do you able to solve the problem? I have the same one.

  • Netgate Administrator

    Exactly the same code? Same hardware?

    If you have an expansion card in there try removing it as a test. Does it POST without that?


  • @stephenw10 the board is A1SA7-2750F
    without ANY additional hardware. Tested with ECC/None-ECC memory, сhanged battery - nothing helps - code 42.

    If I leave A1 memory slot empty - code 19.

    IPMI is locked with unknown password, so I not able to check anything with it.

  • Netgate Administrator

    @Caersar007 said in C2758 - What is BIOS POST code 42:


    Ok, that's not our hardware. You should ask Supermicro support. Though you would think some data would be out there and Google is coming up empty.


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