Many guides suggest simply deleting bootfix.bin from Windows ISO files to bypass the "Press any key to boot from CD" prompt. While this approach might work in some cases, it often renders the ISO unbootable because bootfix.bin contains essential boot sector information.

Instead of deleting files, we need to modify the boot image directly. Here's a reliable method using free tools:

# Required tools:
# 1. oscdimg.exe (from Windows ADK)
# 2. UltraISO or similar ISO editor
# 3. Original Windows ISO

# Step-by-step process:
1. Extract the original ISO contents
2. Create a new bootable ISO with these commands:

oscdimg -bootdata:2#p0,e,b"source\etfsboot.com"#pEF,e,b"source\efisys.bin" -u1 -udfver102 -l"Windows_Install" "source" "output.iso"

For UEFI systems, you can modify the boot configuration to eliminate the prompt:

# Sample boot configuration modification
[boot loader]
timeout=0
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows" /fastdetect

After creating your modified ISO, verify it using virtual machines before burning to physical media. Tools like QEMU are excellent for quick testing:

qemu-system-x86_64 -cdrom modified.iso -m 2048 -enable-kvm

• Missing boot catalog in modified ISO
• Incorrect boot sector parameters
• UEFI/BIOS compatibility issues
• Improper ISO file system settings

For frequent use, consider this PowerShell script that automates the process:

# PowerShell script for automated ISO creation
param(
    [string]$sourcePath,
    [string]$outputFile
)

$adkPath = "C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Deployment Tools"

& "$adkPath\amd64\Oscdimg\oscdimg.exe" 
    -bootdata:2#p0,e,b"$sourcePath\boot\etfsboot.com"#pEF,e,b"$sourcePath\efi\microsoft\boot\efisys.bin" 
    -u1 -udfver102 -l"WinAutoBoot" 
    "$sourcePath" "$outputFile"

if($LASTEXITCODE -ne 0) {
    Write-Error "ISO creation failed"
    exit 1
}

Many developers attempt to remove the "Press any key to boot from CD" prompt by simply deleting bootfix.bin from Windows ISO files, only to find the ISO becomes unbootable. The reality is more nuanced - bootfix.bin contains essential bootloader code beyond just the prompt functionality.

Here's the correct workflow to create an auto-booting Windows ISO:

# Using oscdimg from Windows ADK
oscdimg -b -h -n -m -o -l  

# Key parameters:
# -b : Specifies boot sector file (use original from ISO)
# -m : Allows media to exceed default size
# -o : Optimizes storage by comparing duplicate files
# -n : Allows long filenames

For UEFI boot ISOs, you'll need to modify the boot manager configuration:

1. Extract bootmgfw.efi from ISO's EFI partition
2. Use UEFITool to locate the timeout setting
3. Patch to reduce timeout to 0 seconds

After modification:

• Test in VirtualBox with: VBoxManage.exe modifyhd "disk.vdi" --autoreset off
• Verify ISO checksums match expected values
• Check boot log for any unexpected delays

Here's a PowerShell script to automate the process:

# Requires ADK installed
$adkPath = "C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit"
$oscdimg = Join-Path $adkPath "Deployment Tools\amd64\Oscdimg\oscdimg.exe"

$params = @(
    "-bootdata:2#p0,e,b""bootsect.bin""#pEF,e,b""efisys.bin""",
    "-u2",
    "-udfver102",
    "-l""WIN10_AUTOBOOT""",
    ".\source",
    ".\output.iso"
)

Start-Process -FilePath $oscdimg -ArgumentList $params -Wait