VMware Workstation/ESXi BIOS/EFI SLIC Mod

Discussion in 'Virtualization' started by pantagruel, Aug 26, 2015.

  1. pantagruel

    pantagruel MDL Addicted

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  2. pantagruel

    pantagruel MDL Addicted

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  3. pantagruel

    pantagruel MDL Addicted

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  4. cyberbot

    cyberbot MDL Addicted

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    i have tried this, and it works however using vMotion it doesnt works, i have to power off the VM to be able to migrate it
     
  5. pantagruel

    pantagruel MDL Addicted

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    #425 pantagruel, Aug 2, 2026 at 15:22
    Last edited: Aug 2, 2026 at 17:35
    (OP)
    Sorry, I don't know a lot about vMotion, but here's some ideas:

    1. What is the exact vMotion error? VMware almost always logs the reason in vCenter or /var/log/vmkernel.log.

    2. Does migration work with unmodded firmware? Specify an unmodded ROM in the VMX. What happens?

    3. It's possible that the mod alters something which makes it incompatible with a live migration, making a restart necessary.

    I'm not sure there's anything I can change in the mod itself.
     
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  6. cyberbot

    cyberbot MDL Addicted

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    Hi,

    Thanks for your reply.

    I've done some additional testing and gathered more information.

    Environment

    • ESXi 8.0 Update 3 (Build 25205845)
    • Virtual Hardware Version 21
    • EFI firmware
    • VMX contains:


      firmware = "efi"
      efi20-64.filename = "modded_EFI64.ROM"

    • Live Shared-Nothing vMotion (compute + storage migration between hosts using local datastores).
    1. Exact migration error
    vCenter reports:


    A general system error occurred.

    Launch failure

    The VM failed to resume on the destination during early power on.

    Module Chipset power on failed.

    Cause: Module Chipset power on failed.

    On the destination ESXi host, hostd.log reports:


    Could not open modded_EFI64.ROM (No such file or directory)

    followed by:


    Error message on <VM>:
    Could not open modded_EFI64.ROM (2 (No such file or directory))

    2. Migration with unmodified firmware
    VMs without the following line migrate successfully:


    efi20-64.filename = "modded_EFI64.ROM"

    The problem only occurs on VMs that reference the modified ROM.

    3. Additional observations
    The VM boots and runs normally on the source host, and OEM_SLP activation works perfectly.

    However, during Shared-Nothing vMotion, it appears VMware does not transfer modded_EFI64.ROM to the destination host before attempting the early power-on.

    Because the ROM is missing, the destination host reports:


    Could not open modded_EFI64.ROM

    and then fails with:


    Module Chipset power on failed.

    This makes me think the issue is not with the ROM itself, but that VMware does not include the external ROM referenced by efi20-64.filename in the migration process.

    Have you, or anyone else, ever tested live Shared-Nothing vMotion with the modified EFI ROM on ESXi 8.x?

    Thanks in advance. I appreciate your work on this project.
     
  7. pantagruel

    pantagruel MDL Addicted

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    Yes, it looks like VMware does not include the external ROM referenced by efi20-64.filename in the migration process.

    Where is modded_EFI64.ROM stored? Is it in the VM's directory alongside the VMX, or elsewhere on the datastore? That may help explain why the destination host cannot find it during the migration.
     
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