Update-OSDeployBootISO
Rebuild standard and CA 2023 ISO files from an existing OSDeploy Boot media build.
Update-OSDeployBootISO recreates bootable ISO files from the existing media trees in a selected OSDeploy Boot build. Use it after changing media files or saved OSDCloud profiles when boot.wim does not need to be serviced again.
The command rebuilds bootmedia.iso from bootmedia. When the selected build also contains bootmedia_ca2023, it rebuilds bootmedia_ca2023.iso from that tree. It does not mount, service, export, or replace boot.wim.
Requirements
Run the function from an elevated PowerShell 7.6 or later session on Windows 11 25H2 build 26200 or later. PowerShell must be installed from the MSI package, and curl.exe must be available in PATH.
The workstation must also have:
The OSDeploy module.
A valid Recast Software Community License for direct invocation.
The Windows ADK Deployment Tools, including
oscdimg.exe.Out-GridViewfor selecting a completed build.A completed build under
C:\ProgramData\OSDeployCore\bootwith abootmediadirectory.
The function stops when a host requirement is not met, no build is selected, the Windows ADK is unavailable, or the selected build does not contain bootmedia. A build containing only bootmedia_ca2023 appears in the selector but cannot be processed without the standard media tree.
Parameters
The function has no command-specific parameters and does not accept pipeline input. Build selection is always interactive.
-WhatIf
Common parameter
Not enabled
Run requirement checks and build selection, verify ADK and media paths, populate $global:BuildMedia, and report the rebuild without invoking the ISO step.
-Confirm
Common parameter
Not enabled
Request confirmation before invoking the ISO step. The function declares ConfirmImpact as Medium, so it does not prompt under PowerShell's default High confirmation preference.
Examples
Rebuild available ISO files
Select a completed build and recreate its standard ISO plus its CA 2023 ISO when that source tree exists:
Request confirmation
Review the selected build path before allowing ISO output files to be replaced:
The parent operation is the primary confirmation boundary. An inherited confirmation preference can also prompt in the delegated ISO creation operation.
Preview the rebuild
Open the build selector, validate the ADK and media paths, and report the planned operation without copying profiles or starting oscdimg.exe:
Inspect the rebuilt files
Use the global build state to inspect the ISO files after the command completes:
Build Selection
The function searches immediate child directories under:
A directory is eligible when it contains either bootmedia or bootmedia_ca2023. Eligible builds are sorted by last-modified time, newest first, and displayed in a single-selection Out-GridView picker with ModifiedTime, Name, and Path properties.
Canceling the picker or having no eligible build writes a warning and returns. After selection, the command separately requires bootmedia; bootmedia_ca2023 remains optional.
Media and Architecture
The media paths and outputs are fixed:
bootmedia
bootmedia.iso
Required and always processed.
bootmedia_ca2023
bootmedia_ca2023.iso
Processed only when the directory exists. This tree contains the updated CA 2023 Secure Boot files produced from a compatible imported WinRE source.
Both ISO files are written in the selected build root. Existing files with the same names can be replaced. The selected build directory name becomes the ISO volume label.
The command preserves the architecture of the selected media tree; it does not convert amd64 media to arm64 or the reverse. The ISO helper searches the installed ADK for oscdimg.exe under amd64 first and arm64 second. That tool-selection order does not determine the media architecture.
The resulting ISO is UEFI-only. The helper uses the first available efisys_noprompt.bin or efisys.bin, preferring the media tree before the ADK Oscdimg directory, and creates a UDF 1.02 image without a legacy BIOS boot entry.
OSDCloud Profiles
Before creating each ISO, the shared ISO step checks:
When that source exists, it copies the directory into OSDCloud\Profiles in the applicable media tree. It creates the ISO and then removes the destination profile directory. The same sequence runs independently for bootmedia_ca2023 when present.
Cleanup removes the complete OSDCloud\Profiles directory from each processed media tree, including content that existed there before the command started. Keep persistent profiles in C:\ProgramData\OSDeployCore\OSDCloud\Profiles.
Profile copy and cleanup are not separately gated by ShouldProcess. The parent gate prevents the entire ISO step from running under -WhatIf or after a declined confirmation.
ISO Creation and Failure Behavior
The helper requires oscdimg.exe and a UEFI boot-sector file. Missing tools or boot data write a non-terminating error and skip that ISO. A nonzero oscdimg.exe exit code also writes a non-terminating error; the command does not restore an earlier ISO that was replaced or partially written.
The helper enables file optimization and media larger than a standard CD. Its System.IO.FileInfo result is suppressed by the shared ISO step.
WhatIf and Confirmation
The function performs host checks, initializes OSDeploy Core paths, opens the build selector, verifies the Windows ADK, resolves both media paths, populates $global:BuildMedia, and displays those paths before its single parent ShouldProcess call.
With -WhatIf, the function reports Rebuild BootMedia ISO files and does not call the ISO step. No profile directories are copied or removed, oscdimg.exe is not started, and existing ISO files are unchanged.
With -Confirm, declining the parent operation leaves the populated global state in place and returns without changing the media tree or ISO files.
Output
Update-OSDeployBootISO does not intentionally write an object to the pipeline. Inspect bootmedia.iso and optional bootmedia_ca2023.iso in $global:BuildMedia.MediaRootPath to verify completion.
The command replaces $global:BuildMedia with an ordered dictionary containing AdkRootPath, MediaIsoLabel, MediaPath, MediaPathEX, and MediaRootPath. This process-wide state is available after -WhatIf or declined confirmation, but it is not pipeline output.
See The OSDeploy Boot ISO for the related workflow or the Update-OSDeployBootISO command reference for compact syntax.
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