QEMU - Windows unable to boot in UEFI mode

[faleais]

I’m trying to build qcow2 format image for Windows server 2025 and when asking Packer to use UEFI mode, it’s unable to boot from ISO and it just drops me in EFI Shell where I see the content of the ISO is FS1: not in FS0:

I’m able to boot form ISO in BIOS mode but want to build image in UEFI mode.

here is my packer script

packer {
  required_version = ">= 1.11.0"
  required_plugins {
    qemu = {
      version = ">= 1.1.1"
      source  = "github.com/hashicorp/qemu"
    }
  }
}

source "qemu" "windows" {
  vm_name                = "panw-cisl1-windows-2025"
# Windows 2025  - Internet
  # iso_url                = "https://artifactory.paloaltonetworks.com:443/artifactory/openshift-images-local/26100.1742.240906-0331.ge_release_svc_refresh_SERVER_EVAL_x64FRE_en-us.iso"
  # iso_checksum           = "d0ef4502e350e3c6c53c15b1b3020d38a5ded011bf04998e950720ac8579b23d"
# Windows 2025 - Thomas image
  iso_url                = "https://artifactory.paloaltonetworks.com/artifactory/openshift-images-local/SW_DVD9_Win_Server_STD_CORE_2025_24H2.9_64Bit_English_DC_STD_MLF_X24-08243.ISO"
  iso_checksum           = "2509618770af72a6335f975beb9f3caacfecbd60c448cafa37959aabccb0d12d"
# Windows 2025 with autounattended

  format                 = "qcow2"
  output_directory       = "build"
  machine_type           = "q35"
  accelerator            = "kvm"
  cpus                   = "4"
  memory                 = "14096"
  disk_size              = "40960M"
  headless               = "true"


qemuargs = [
  ["-drive", "file=/home/jenkins-agent/.cache/packer/45173890bb9e0fc063f71cfb6d5ec40a0210e2d9.iso,media=cdrom,index=4"],
  ["-drive", "if=pflash,format=raw,readonly=on,file=/usr/share/OVMF/OVMF_CODE.fd"],
  ["-drive", "if=pflash,format=raw,file=/home/jenkins-agent/ovmf/OVMF_VARS.fd"],
  ["-boot", "order=d"]
]
  communicator           = "winrm"
  winrm_username         = "Administrator"
  winrm_password         = "WindowsPassword"

  net_device = "e1000"
  disk_interface         = "ide"
  floppy_files = ["../answer-files/autounattend.xml", "../answer-files/winrm-config.ps1"]
  boot_command = ["<spacebar><spacebar>"]

any idea why ?

[anurag.sharma]

Can you test with different values of the disk_interface

[faleais]

trying scsi, virtio, and virtio-scsi didn’t help

[anurag.sharma]

It seems like in UEFI, the EFI shell is first in the boot order. I don’t think its possible to alter this in UEFI today in packer. Perhaps need to figure out a workaround.

[anurag.sharma]

As a workaround, u can try running fs1:\bootmgr.efi as the first boot_command in packer. This will hopefully boot the right iso.
Additionally add a wait for maybe 60s <wait60> after this to let the iso boot.

[faleais]

@anurag.sharma

source "qemu" "windows2k25" {
  vm_name                = "windows-2025-V24h2-B26100-4652"
# Windows 2025  - Internet
  # iso_url                = 
# instanceType is u1.2xmedium 2 vCPUs and 4GB of RAM
  format                 = "qcow2"
  output_directory       = "build"
  machine_type           = "q35"
  accelerator            = "kvm"
  cpus                   = "2"
  memory                 = "4096"
  disk_size              = "102G"
  headless               = "true"
  disk_compression       = "true"
  firmware                = "uefi"
  efi_boot                =  true
  efi_firmware_code       = "/usr/share/OVMF/OVMF_CODE.fd"
  efi_firmware_vars       = "/home/jenkins-agent/ovmf/OVMF_VARS.fd"
  # qemuargs                = [["-drive", "file=build/{{ .Name }},if=virtio,cache=writeback,discard=ignore,format=qcow2,index=1"]]
  # vtpm                    = true

qemuargs = [
  ["-drive", "file=/home/jenkins-agent/.cache/packer/45173890bb9e0fc063f71cfb6d5ec40a0210e2d9.iso,media=cdrom,index=4"],
  ["-drive", "if=pflash,format=raw,readonly=on,file=/usr/share/OVMF/OVMF_CODE.fd"],
  ["-drive", "if=pflash,format=raw,file=/home/jenkins-agent/ovmf/OVMF_VARS.fd"],
  ["-boot", "order=d"]
]

  shutdown_command     = "c:\\windows\\system32\\sysprep\\sysprep.exe /generalize /oobe /shutdown /unattend:a:\\unattend.xml"


  #host_port_min = 5985
  #host_port_max = 5985
  skip_nat_mapping       = true

  communicator           = "winrm"
  winrm_username         = "Administrator"
  winrm_password         = "${var.winrm_admin_password}"


  net_device             = "e1000"
  # net_device             = "virtio-net" # didn't work

  disk_interface         = "ide"
  # disk_interface         = "scsi" # didn't work
  # disk_interface         = "sata" # didn't work
  # disk_interface         = "virtio"  # didn't work
  # disk_interface         = "virtio-scsi" # didn't work

  cd_files               =  ["./virtio_drivers/virtio-win-0.1.271-drivers.iso"]
  
  floppy_files          = ["../answer-files/autounattend.xml", "../answer-files/unattend.xml", "../scripts/network-configs.ps1","../scripts/post-config.ps1"]

boot_command = [
  "fs1://bootmgr.efi",
  "<wait60>"
    ]

I’m now getting this, I cannot even run bootmgr.efi file

any idea what is going on ? is there a known issue between Packer and Windows server 2025 UEFI mode ?

[adeelarifbhatti]

Did it work for you ? I am also struggling with it and nothing has been helpful yet.

[thawkes]

I seem to be having issues with this as well. When adding device_type = “UEFI” to my .hcl, it causes Packer to turn on the VM before the CD-ROM is initialized, and I get an error stating it is timed out trying to connect to the CD-ROM for uefi in the Nutanix console window along with press any key to continue. If I send the Nutanix console a ctrl + alt + delete, it restarts and the error is gone because the CD-ROM now had time to initialize. I have tried setting boot_priority = “cdrom” and I have added a wait time as well. I created a new ISO that had the Nutanix VirtIO drivers added in because of the issue with Windows needing the scsi driver to even see the disk. If I take out the device_type = “uefi” out of my hcl file, it sees the partitions but states it cannot install windows because it is using GPT partitioning. Has anyone found a way to get Windows to boot using uefi and using Packer to create the VM?