Win10+ Setup Disk (Works with UEFI Secure Boot / BIOS / Install.wim over 4 GB)

@uffbros The Windows version has no connection with the partitioning. The script creates partitions and just copies whatever Windows ISO version you select onto the usb disk.

The FAT32 boot partition gets hidden that's probably why you only see one partition

 

Yes since 2.1

 

What i have in mind as a fork of this script is something like a "windows 11 setup disk" implementing this

https://forums.mydigitallife.net/threads/windows-11-boot-device-creation-with-ufws.84489/

Either a separate script or if doable add the option in Win10 setup disk script for installing windows 11

 

sure is Quick and dirty -- the command window "quickly" disappears and shows a "dirty" error

 

It's past midnight here. Time to quit. This is the progress I've made so far...

 

Update: If the Selected Procedure for creating was a drop down list instead?

Code:

<# : standard way of doing hybrid batch + powershell scripts
@title Win10+ Setup Disk 3.0
@set "__ARGS__=%*" &powershell -noprofile "$ScriptPath='%~f0';iex((Get-Content('%~f0') -Raw))" &exit/b
#>
#
#   Homepage: https://forums.mydigitallife.net/threads/win10-setup-disk-works-with-uefi-with-secure-boot-bios-install-wim-over-4-gb.79268/
#   Credits: @rpo, @freddie-o, @BAU & @abbodi1406
#
#   This script must be executed with admin privilege
#
#   Test Administrator privileges
If (-NOT ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator"))
{
    $uac_error="Elevating UAC for Administrator Privileges failed"
    #   The following test is to avoid infinite looping if elevating UAC for Administrator Privileges failed
    if ($env:__ARGS__ -eq $uac_error) {
    read-host "$uac_error`r`nRight click on the script and select ""Run as administrator""`r`nPress Enter to exit...";exit}
#   Restart the script to get Administrator privileges and exit
                                                                                       
    Start-Process "$ScriptPath" $uac_error -Verb runAs; exit
}
$pswindow = $host.ui.rawui          # create a reference to the console’s UI.RawUI child object
$pswindow.windowtitle = ([string]($pswindow.windowtitle -split "^.*  ")).trim() ; $ShortTitle=($pswindow.windowtitle -split " @ .*")[0]
#
Add-Type -AssemblyName System.Windows.Forms # Load the class System.Windows.Forms
# Filebrowser dialog object
$FileBrowser = New-Object System.Windows.Forms.OpenFileDialog -Property @{
    Multiselect = $false # One file can be chosen
    Filter = 'ISO images (*.iso)|*.iso' # Select only iso files
}
#
Add-Type -Name Window -Namespace Console -MemberDefinition '
[DllImport("Kernel32.dll")]
public static extern IntPtr GetConsoleWindow();
[DllImport("user32.dll")]
public static extern bool ShowWindow(IntPtr hWnd, Int32 nCmdShow);
'
function Show-Console {[Console.Window]::ShowWindow([Console.Window]::GetConsoleWindow(), 1)|Out-Null}# Show console
function Hide-Console {[Console.Window]::ShowWindow([Console.Window]::GetConsoleWindow(), 0)|Out-Null}# Hide console
#
Function MsgBox {[System.Windows.Forms.MessageBox]::Show($Args[0],$ShortTitle,$Args[1],$Args[2])}
#
Hide-Console
clear-host
$swmsize=4000
$USB=$Null
$Form=New-Object System.Windows.Forms.Form # Create the screen form (window)
$Form.TopMost = $True
# Set the title and size of the window:
$Form.Text=$ShortTitle
$Form.Font='Consolas,10'
$Form.Width=420 ; $Form.Height=315
$Form.StartPosition = "CenterScreen"
$Form.SizeGripStyle = "Hide"
[System.Windows.Forms.Application]::EnableVisualStyles();
#
$USBDisk=New-Object System.Windows.Forms.Label # Put Selected USB Disk label on the form
$USBDisk.Location=New-Object System.Drawing.Point(20,20)
$USBDisk.Text="Selected USB Disk"                     
$USBDisk.Size=New-Object System.Drawing.Size(200,20)
$Form.Controls.Add($USBDisk)
#
$USBDiskList=New-Object System.Windows.Forms.ComboBox # Create a USB drop-down list and fill it
$USBDiskList.DropDownStyle=[System.Windows.Forms.ComboBoxStyle]::DropDownList;
$USBDiskList.Location=New-Object System.Drawing.Point(20,40)
$USBDiskList.Size=New-Object System.Drawing.Size(363,22)
$Form.Controls.Add($SelectUSBDiskList)
$USBDisks=@() # array with USB disk number
#
$Disks=$Null;While (!$Disks){
    If(!($Disks=Get-Disk | Where-Object {($_.BusType -eq "USB") -and ($_.OperationalStatus -eq "Online")})){
        if((MsgBox "Plug in your USB disk first. `n`nClick OK to continue." "OKCancel" "Information") -eq "Cancel") {exit}}}
#
$SelectProcedure=New-Object System.Windows.Forms.Label # Put Selected Procedure for creating Setup disk on the form
$SelectProcedure.Location=New-Object System.Drawing.Point(20,85)                 
$SelectProcedure.Size=New-Object System.Drawing.Size(350,20)
$SelectProcedure.text="Selected Procedure If Install Wim is Over 4GB"
$Form.Controls.Add($SelectProcedure)
#
$ProcedureList=New-Object System.Windows.Forms.ComboBox # Create a procedure drop-down list and fill it
$ProcedureList.DropDownStyle=[System.Windows.Forms.ComboBoxStyle]::DropDownList;
$ProcedureList.Location=New-Object System.Drawing.Point(20,105)
$ProcedureList.Size=New-Object System.Drawing.Size(363,22)
$Form.Controls.Add($ProcedureList)
#
$ISOImage=New-Object System.Windows.Forms.Label # Put the ISO Image label on the form
$ISOImage.Location=New-Object System.Drawing.Point(20,150)                 
$ISOImage.Size=New-Object System.Drawing.Size(200,20)
$ISOImage.text="Selected ISO Image"
$Form.Controls.Add($ISOImage)
#
$ISOFile=New-Object System.Windows.Forms.Label # Put the ISO file name on the form
$ISOFile.Location=New-Object System.Drawing.Point(20,170)
$ISOFile.Text=" "
$ISOFile.Size=New-Object System.Drawing.Size(364,24)
$ISOFile.Backcolor = [System.Drawing.Color]::White
$ISOFile.BorderStyle = [System.Windows.Forms.BorderStyle]::FixedSingle
$Form.Controls.Add($ISOFile)
#
$CancelButton=New-Object System.Windows.Forms.Button # Put the Cancel button on the form
$CancelButton.Location=New-Object System.Drawing.Point(270,230)
$CancelButton.Text="Cancel"                         
$CancelButton.Size=New-Object System.Drawing.Size(115,26)
$Form.Controls.Add($CancelButton)
$CancelButton.DialogResult = [System.Windows.Forms.DialogResult]::Cancel
#
$SelectISOButton=New-Object System.Windows.Forms.Button # Put the Select ISO button on the form
$SelectISOButton.Location=New-Object System.Drawing.Point(145,230)
$SelectISOButton.Text="Select ISO"                             
$SelectISOButton.Size=New-Object System.Drawing.Size(115,26)
$Form.Controls.Add($SelectISOButton)
#
$CreateDiskButton=New-Object System.Windows.Forms.Button # Put the Create Disk button on the form
$CreateDiskButton.Location=New-Object System.Drawing.Point(20,230)
$CreateDiskButton.Text="Create Disk"                                 
$CreateDiskButton.Size=New-Object System.Drawing.Size(115,26)
$Form.Controls.Add($CreateDiskButton)
$CreateDiskButton.Enabled = $false
$CreateDiskButton.DialogResult = [System.Windows.Forms.DialogResult]::OK
#
$SelectISOButton.Add_Click({
    If ($FileBrowser.ShowDialog() -ne "Cancel"){ # if Cancel, just ignore
        $Global:ImagePath = $FileBrowser.filename    # return the file name
        $ISOFile.Text= Split-Path -Path $ImagePath -leaf # extract filename and extension (iso)
        if (($ISOFile.Text).length -gt 44) {$ISOFile.Text = $ImagePath.PadRight(100," ").substring(0,43)+"..."}
        $CreateDiskButton.Enabled = $true
        $CreateDiskButton.Focus()}})
#
Foreach ($USBDisk in $Disks) {
    $FriendlyName=($USBDisk.FriendlyName).PadRight(40," ").substring(0,39)
    $USBDisks+=$USBDisk.DiskNumber
    $USBDiskList.Items.Add(("{0,-39}{1:n2} GB" -f $FriendlyName,($USBDisk.Size/1GB)))|out-null
    $Partitions = Get-Partition | Where-Object { $_.DiskNumber -eq $USBDisk.DiskNumber}
    If ($Partitions) {
        Foreach ($Partition in $Partitions) {
       If(!$Partition.DriveLetter){$AccessPath="  "} Else {$AccessPath=$Partition.DriveLetter+":"}       
        $Volumes=get-volume | Where-Object {$Partition.AccessPaths -contains  $_.path }
            Foreach ($Volume in $Volumes) {
                $USBDisks+=$USBDisk.DiskNumber
                $USBDiskList.Items.Add(("{0,0}({1,2}){2,-32}[{3:n2} GB]" -f " ", ($AccessPath), $Volume.FileSystemLabel.PadRight(25," ").substring(0,25), ($Partition.Size/1GB)))|out-null
            }
        }
    }
}
$form.Controls.Add($USBDiskList)
$USBDiskList.SelectedIndex=0
#
$Groupbox=New-Object System.Windows.Forms.Groupbox # Add a group box on the form
$Groupbox.Location=New-Object System.Drawing.Point(7,0)
$Groupbox.Text=""
$Groupbox.Size=New-Object System.Drawing.Size(390,270)
$Form.Controls.Add($Groupbox)
#
if($form.ShowDialog() -eq "Cancel") {MsgBox "The script was cancelled." "OK" "Information"|out-Null;exit}
#
# At this point the mounted USB disk and the iso image file path are defined
#
$USB=$USBDisks[$USBDiskList.SelectedIndex]
#
If ($checkBox40.Checked){$splitwim=1}Else{$splitwim=0}
#
If((MsgBox "WARNING! `n`nYour USB disk will be converted to MBR scheme, repartitioned and reformatted.`n`nAll partitions and data currently stored in the USB disk will be erased.`r`n`r`nAre you sure you want to continue?" "YESNO" "Warning") -eq "NO"){exit}
# Mount the image file if not already mounted and get the drive letter
#
Show-Console  # restablish console view for the no gui part of the script
$form.ShowInTaskbar = $False
$form.Hide()
#
#   Check if iso already mounted by getting driveletter
If($ISO=(Get-DiskImage -ImagePath $ImagePath | Get-Volume).DriveLetter){$Mounted=$True}    Else
#    Mount iso and get drive letter
    {$Mounted=$False; Mount-DiskImage -ImagePath $ImagePath -StorageType ISO |out-null
     If(!($ISO=(Get-DiskImage -ImagePath $ImagePath | Get-Volume).DriveLetter)){Exit}}
$ISO=$ISO+":"   
# set bootmenupolicy Legacy
Copy-Item $ISO"\boot\bcd" $env:temp\bcdmbr -Force
& bcdedit /store ($env:temp + "\bcdmbr") /set '{default}' bootmenupolicy Legacy
Set-ItemProperty -Path ($env:temp + "\bcdmbr") -Name IsReadOnly -Value $true
Copy-Item $ISO"\EFI\Microsoft\boot\bcd" $env:temp\bcdefi -Force
& bcdedit /store ($env:temp + "\bcdefi") /set '{default}' bootmenupolicy Legacy
Set-ItemProperty -Path ($env:temp + "\bcdefi") -Name IsReadOnly -Value $true
#
Clear-Host
if (Test-Path "$iso\sources\install.wim"){$WimFile="install.wim"}
if (Test-Path "$iso\sources\install.esd"){$WimFile="install.esd"}
$NTFS=1
If((Get-Item "$iso\Sources\$WimFile").Length/1MB -lt $swmsize){
$NTFS=0}
else{
If ((Test-Path "$iso\sources\install.wim") -and ($Splitwim -gt 0)){$NTFS=0}
}   
#    Clear the USB disk
"Select disk $USB`r`nclean`r`nconvert MBR`r`nrescan`r`nexit" |diskpart
#
Stop-Service ShellHWDetection -erroraction silentlycontinue|out-null
#   Create the fat32 boot partition
IF ($NTFS -gt 0){
$usbfat32=(New-Partition -DiskNumber $usb -Size  1GB -AssignDriveLetter | Format-Volume -FileSystem FAT32 -NewFileSystemLabel "BOOT").DriveLetter + ":"
#    Create the NTFS intall partition
$usbntfs=(New-Partition -DiskNumber $usb -UseMaximumSize -AssignDriveLetter -IsActive | Format-Volume -FileSystem NTFS -NewFileSystemLabel "SETUP").DriveLetter + ":"}
else {
$usbfat32=(New-Partition -DiskNumber $usb -UseMaximumSize -AssignDriveLetter -IsActive| Format-Volume -FileSystem FAT32 -NewFileSystemLabel "SETUP").DriveLetter + ":"}
Start-Service ShellHWDetection -erroraction silentlycontinue|out-null
#
IF ($NTFS -gt 0){
#   Copy needed files to the fat32 boot partition
robocopy $iso"\" $usbfat32"\" bootmgr bootmgr.efi
robocopy $iso"\boot" $usbfat32"\boot" /e /xf $iso\boot\bcd
robocopy $iso"\efi" $usbfat32"\efi" /e /xf $iso\efi\microsoft\boot\bcd
robocopy $iso"\sources" $usbfat32"\sources" boot.wim
Copy-Item ($env:temp + "\bcdmbr") $usbfat32"\boot\bcd" -Force
Copy-Item ($env:temp + "\bcdefi") $usbfat32"\EFI\Microsoft\boot\bcd" -Force
#    Remove the drive letter to hide the device
Get-Volume -DriveLetter $usbfat32.substring(0,$usbfat32.Length-1) | Get-Partition | Remove-PartitionAccessPath -accesspath $usbfat32
#
#   Copy needed files to the NTFS install partition
robocopy $iso $usbntfs /e /xf $iso\boot\bcd $iso\efi\microsoft\boot\bcd
Copy-Item ($env:temp + "\bcdmbr") $usbntfs"\boot\bcd" -Force
Copy-Item ($env:temp + "\bcdefi") $usbntfs"\EFI\Microsoft\boot\bcd" -Force
}
else{
robocopy $iso $usbfat32 /e /xf $iso\boot\bcd $iso\efi\microsoft\boot\bcd $iso\sources\install.wim
Copy-Item ($env:temp + "\bcdmbr") $usbfat32"\boot\bcd" -Force
Copy-Item ($env:temp + "\bcdefi") $usbfat32"\EFI\Microsoft\boot\bcd" -Force
If((Get-Item "$iso\Sources\install.wim").Length/1MB -lt $swmsize){
robocopy "$iso\sources" "$usbfat32\sources" install.wim}
else
{Dism /Split-Image /ImageFile:"$iso\sources\install.wim" /SWMFile:"$usbfat32\sources\install.swm" /FileSize:$swmsize}
}
#
#   House keeping
remove-item ($env:temp + "\bcdmbr") -force
remove-item ($env:temp + "\bcdmbr.*") -force
remove-item ($env:temp + "\bcdefi") -force
remove-item ($env:temp + "\bcdefi.*") -force
#
# Eject the mounted iso image if it was loaded by the script
If(!$Mounted){DisMount-DiskImage -ImagePath $ImagePath |out-null}
MsgBox (($ShortTitle -split " @.*")[0]+" was created successfully.") "OK" "Information" |Out-Null;exit

 

It took me a while to figure out what the 3 was in your script. Seems more fitting

Win10+ Setup Disk 3.0

 

I cannot figure out which modifications I made is causing the script to create a FAT32 and NTFS partition when I select "Split the Install.wim"

Code:

<# : standard way of doing hybrid batch + powershell scripts
@title Win10+ Setup Disk 3.0 &color 3E
@set "__ARGS__=%*" &powershell -noprofile "$ScriptPath='%~f0';iex((Get-Content('%~f0') -Raw))" &exit/b
#>
#
#   Homepage: https://forums.mydigitallife.net/threads/win10-setup-disk-works-with-uefi-with-secure-boot-bios-install-wim-over-4-gb.79268/
#   Credits: @rpo, @freddie-o, @BAU & @abbodi1406
#
#   This script must be executed with admin privilege
#
#   Test Administrator privileges
If (-NOT ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator"))
{
    $uac_error="Elevating UAC for Administrator Privileges failed"
    #   The following test is to avoid infinite looping if elevating UAC for Administrator Privileges failed
    if ($env:__ARGS__ -eq $uac_error) {
    read-host "$uac_error`r`nRight click on the script and select ""Run as administrator""`r`nPress Enter to exit...";exit}
#   Restart the script to get Administrator privileges and exit
                                                                                    
    Start-Process "$ScriptPath" $uac_error -Verb runAs; exit
}
$pswindow = $host.ui.rawui          # create a reference to the console’s UI.RawUI child object
$pswindow.windowtitle = ([string]($pswindow.windowtitle -split "^.*  ")).trim() ; $ShortTitle=($pswindow.windowtitle -split " @ .*")[0]
#
Add-Type -AssemblyName System.Windows.Forms # Load the class System.Windows.Forms
# Filebrowser dialog object
$FileBrowser = New-Object System.Windows.Forms.OpenFileDialog -Property @{
    Multiselect = $false # One file can be chosen
    Filter = 'ISO images (*.iso)|*.iso' # Select only iso files
}
#
Function MsgBox {[System.Windows.Forms.MessageBox]::Show($Args[0],$ShortTitle,$Args[1],$Args[2])}
#
Function Update_bcd
{
param ($iso, $usbpartition)
"Set bootmenupolicy Legacy for $usbpartition"
Copy-Item "$iso\boot\bcd" "$usbpartition\boot\bcd" -Force
Copy-Item "$iso\EFI\Microsoft\boot\bcd" "$usbpartition\EFI\Microsoft\boot\bcd" -Force
& bcdedit /store "$usbpartition\boot\bcd" /set '{default}' bootmenupolicy Legacy |Out-Null
& bcdedit /store "$usbpartition\EFI\Microsoft\boot\bcd" /set '{default}' bootmenupolicy Legacy |Out-Null
Set-ItemProperty -Path "$usbpartition\boot\bcd" -Name IsReadOnly -Value $true
Set-ItemProperty -Path "$usbpartition\EFI\Microsoft\boot\bcd" -Name IsReadOnly -Value $true
remove-item "$usbpartition\boot\bcd.*" -force
remove-item "$usbpartition\EFI\Microsoft\boot\bcd.*" -force
}
#
clear-host
$swmsize=4000
$USB=$Null
$Form=New-Object System.Windows.Forms.Form # Create the screen form (window)
$Form.TopMost = $True
# Set the title and size of the window:
$Form.Text=$ShortTitle
$Form.Font='Consolas,9'                     
$Form.Width=420 ; $Form.Height=315
$Form.StartPosition = "CenterScreen"
$Form.SizeGripStyle = "Hide"
[System.Windows.Forms.Application]::EnableVisualStyles();
#
$USBDisk=New-Object System.Windows.Forms.Label # Put Selected USB Disk label on the form
$USBDisk.Location=New-Object System.Drawing.Point(20,20)
$USBDisk.Text="Selected USB Disk"
$USBDisk.Size=New-Object System.Drawing.Size(200,20)
$Form.Controls.Add($USBDisk)
#
$USBDiskList=New-Object System.Windows.Forms.ComboBox # Create a drop-down list and fill it
$USBDiskList.DropDownStyle=[System.Windows.Forms.ComboBoxStyle]::DropDownList;
$USBDiskList.Location=New-Object System.Drawing.Point(20,40)
$USBDiskList.Size=New-Object System.Drawing.Size(363,22)
$Form.Controls.Add($SelectUSBDiskList)
$USBDisks=@() # array with USB disk number
#
$Disks=$Null;While (!$Disks){
    If(!($Disks=Get-Disk | Where-Object {($_.BusType -eq "USB") -and ($_.OperationalStatus -eq "Online")})){
        if((MsgBox "Plug in your USB disk first. `n`nClick OK to continue." "OKCancel" "Information") -eq "Cancel") {exit}}}
#
$SelectProcedure=New-Object System.Windows.Forms.Label # Put Selected Procedure for creating Setup disk on the form
$SelectProcedure.Location=New-Object System.Drawing.Point(20,85)
$SelectProcedure.Size=New-Object System.Drawing.Size(380,20)
$SelectProcedure.text="Selected Procedure if Install Wim is more than 4GB"
$Form.Controls.Add($SelectProcedure)
#
$ProcedureList=New-Object System.Windows.Forms.ComboBox # Create a procedure drop-down list and fill it
$ProcedureList.DropDownStyle=[System.Windows.Forms.ComboBoxStyle]::DropDownList;
$ProcedureList.Location=New-Object System.Drawing.Point(20,105)
$ProcedureList.Size=New-Object System.Drawing.Size(363,22)
[void] $ProcedureList.Items.Add("Split the Install.wim")
[void] $ProcedureList.Items.Add("Create a FAT32 and NTFS partition")
[void] $ProcedureList.Items.Add("Install.wim is less than 4GB")
$Form.Controls.Add($ProcedureList)
#
$ProcedureList.SelectedIndex=0
#
$ISOImage=New-Object System.Windows.Forms.Label # Put the ISO Image label on the form
$ISOImage.Location=New-Object System.Drawing.Point(20,150)
$ISOImage.Size=New-Object System.Drawing.Size(200,20)
$ISOImage.text="Selected ISO Image"
$Form.Controls.Add($ISOImage)
#
$ISOFile=New-Object System.Windows.Forms.Label # Put the ISO file name on the form
$ISOFile.Location=New-Object System.Drawing.Point(20,170)
$ISOFile.Text=" "
$ISOFile.Size=New-Object System.Drawing.Size(364,24)
$ISOFile.Backcolor = [System.Drawing.Color]::White
$ISOFile.BorderStyle = [System.Windows.Forms.BorderStyle]::FixedSingle
$Form.Controls.Add($ISOFile)
#
$CancelButton=New-Object System.Windows.Forms.Button # Put the Cancel button on the form
$CancelButton.Location=New-Object System.Drawing.Point(270,230)
$CancelButton.Text="Cancel"
$CancelButton.Size=New-Object System.Drawing.Size(115,26)
$Form.Controls.Add($CancelButton)
$CancelButton.DialogResult = [System.Windows.Forms.DialogResult]::Cancel
#
$SelectISOButton=New-Object System.Windows.Forms.Button # Put the Select ISO button on the form
$SelectISOButton.Location=New-Object System.Drawing.Point(145,230)
$SelectISOButton.Text="Select ISO"
$SelectISOButton.Size=New-Object System.Drawing.Size(115,26)
$Form.Controls.Add($SelectISOButton)
#
$CreateDiskButton=New-Object System.Windows.Forms.Button # Put the Create Disk button on the form
$CreateDiskButton.Location=New-Object System.Drawing.Point(20,230)
$CreateDiskButton.Text="Create Disk"
$CreateDiskButton.Size=New-Object System.Drawing.Size(115,26)
$Form.Controls.Add($CreateDiskButton)
$CreateDiskButton.Enabled = $false
$CreateDiskButton.DialogResult = [System.Windows.Forms.DialogResult]::OK
#
$SelectISOButton.Add_Click({
    If ($FileBrowser.ShowDialog() -ne "Cancel"){ # if Cancel, just ignore
        $Global:ImagePath = $FileBrowser.filename    # return the file name
        $ISOFile.Text= Split-Path -Path $ImagePath -leaf # extract filename and extension (iso)
        if (($ISOFile.Text).length -gt 44) {$ISOFile.Text = $ImagePath.PadRight(100," ").substring(0,49)+"..."}
        $CreateDiskButton.Enabled = $true
        $CreateDiskButton.Focus()}})
#
Foreach ($USBDisk in $Disks) {
    $FriendlyName=($USBDisk.FriendlyName).PadRight(40," ").substring(0,39)
    $USBDisks+=$USBDisk.DiskNumber
    $USBDiskList.Items.Add(("{0,-39}{1:n2} GB" -f $FriendlyName,($USBDisk.Size/1GB)))|out-null
    $Partitions = Get-Partition | Where-Object { $_.DiskNumber -eq $USBDisk.DiskNumber}
    If ($Partitions) {
        Foreach ($Partition in $Partitions) {
        If(!$Partition.DriveLetter){$AccessPath="  "} Else {$AccessPath=$Partition.DriveLetter+":"}   
        $Volumes=get-volume | Where-Object {$Partition.AccessPaths -contains  $_.path }
            Foreach ($Volume in $Volumes) {
                $USBDisks+=$USBDisk.DiskNumber
                $USBDiskList.Items.Add(("{0,0}({1,2}){2,-32}[{3:n2} GB]" -f " ", ($AccessPath), $Volume.FileSystemLabel.PadRight(25," ").substring(0,25), ($Partition.Size/1GB)))|out-null
            }
        }
    }
}
$form.Controls.Add($USBDiskList)
$USBDiskList.SelectedIndex=0
#
$Groupbox=New-Object System.Windows.Forms.Groupbox # Add a group box on the form
$Groupbox.Location=New-Object System.Drawing.Point(7,0)
$Groupbox.Text=""
$Groupbox.Size=New-Object System.Drawing.Size(390,270)
$Form.Controls.Add($Groupbox)
#
echo "Select your USB Disk, the procedure (how you want your Setup disk created) and your ISO image."
echo "Your $ShortTitle will start as soon as you click the 'Create Disk' button."
#
if($form.ShowDialog() -eq "Cancel") {MsgBox "The script was cancelled." "OK" "Information"|out-Null;exit}
#
# At this point the mounted USB disk and the iso image file path are defined
#
$USB=$USBDisks[$USBDiskList.SelectedIndex]
#
If ($ProcedureList.SelectedIndex -eq 0){$splitwim=1}Else{$splitwim=0}
#
If((MsgBox "WARNING! `n`nYour USB disk will be converted to MBR scheme, repartitioned and reformatted.`n`nAll partitions and data currently stored in the USB disk will be erased.`r`n`r`nAre you sure you want to continue?" "YESNO" "Warning") -eq "NO"){exit}
# Mount the image file if not already mounted and get the drive letter
#
#   Check if iso already mounted by getting driveletter
If($ISO=(Get-DiskImage -ImagePath $ImagePath | Get-Volume).DriveLetter){$Mounted=$True}    Else
#    Mount iso and get drive letter
    {$Mounted=$False; Mount-DiskImage -ImagePath $ImagePath -StorageType ISO |out-null
     If(!($ISO=(Get-DiskImage -ImagePath $ImagePath | Get-Volume).DriveLetter)){Exit}}
$ISO=$ISO+":" 
Clear-Host
if (Test-Path "$iso\sources\install.wim"){$WimFile="install.wim"}
if (Test-Path "$iso\sources\install.esd"){$WimFile="install.esd"}
$NTFS=1
If((Get-Item "$iso\Sources\$WimFile").Length/1MB -lt $swmsize){
$NTFS=0}
else{
If ((Test-Path "$iso\sources\install.wim") -and ($Splitwim -gt 0)){$NTFS=0}
} 
#    Clear the USB stick
Clear-Disk $usb -RemoveData -RemoveOEM -Confirm:$false
set-disk $usb -partitionstyle mbr
Stop-Service ShellHWDetection -erroraction silentlycontinue|out-null
#####################################################################
#    Create partition(s)
#
IF ($NTFS -gt 0){
$usbfat32=(New-Partition -DiskNumber $usb -Size  1GB -AssignDriveLetter | Format-Volume -FileSystem FAT32 -NewFileSystemLabel "BOOT").DriveLetter + ":"
#    Create the NTFS intall partition
$usbntfs=(New-Partition -DiskNumber $usb -UseMaximumSize -AssignDriveLetter -IsActive | Format-Volume -FileSystem NTFS -NewFileSystemLabel "SETUP").DriveLetter + ":"}
else {
$usbfat32=(New-Partition -DiskNumber $usb -UseMaximumSize -AssignDriveLetter -IsActive| Format-Volume -FileSystem FAT32 -NewFileSystemLabel "SETUP").DriveLetter + ":"}
Start-Service ShellHWDetection -erroraction silentlycontinue|out-null
#####################################################################
IF ($NTFS -gt 0){
#
#    One fat32 partition and one ntfs partition
#
#    Copy needed files to the fat32 boot partition
robocopy $iso"\" $usbfat32"\" bootmgr bootmgr.efi
robocopy $iso"\boot" $usbfat32"\boot" /e /xf $iso\boot\bcd
robocopy $iso"\efi" $usbfat32"\efi" /e /xf $iso\efi\microsoft\boot\bcd
Update_BCD $iso $usbfat32
robocopy $iso"\sources" $usbfat32"\sources" boot.wim
#     Remove the drive letter to hide the device
Get-Volume -DriveLetter $usbfat32.substring(0,$usbfat32.Length-1) | Get-Partition | Remove-PartitionAccessPath -accesspath $usbfat32
#
#
#    Copy needed files to the NTFS install partition
robocopy $iso $usbntfs /e /xf $iso\boot\bcd $iso\efi\microsoft\boot\bcd
Update_BCD $iso $usbntfs
}
#####################################################################
else{
#
#    One fat32 partition
#
robocopy $iso $usbfat32 /e /xf $iso\boot\bcd $iso\efi\microsoft\boot\bcd $iso\sources\install.wim
Update_BCD $iso $usbfat32
If((Get-Item "$iso\Sources\install.wim").Length/1MB -lt $swmsize){
robocopy "$iso\sources" "$usbfat32\sources" install.wim}
else
{Dism /Split-Image /ImageFile:"$iso\sources\install.wim" /SWMFile:"$usbfat32\sources\install.swm" /FileSize:$swmsize}
}
#####################################################################
#
# Eject the mounted iso image if it was loaded by the script
If(!$Mounted){DisMount-DiskImage -ImagePath $ImagePath |out-null}
MsgBox (($ShortTitle -split " @.*")[0]+" was created successfully.") "OK" "Information" |Out-Null;exit

 

When choosing the "Split the Install.wim" procedure I get 2 errors

After setting bootmenupolicy Legacy the script stops and the "MsgBox ...was created successfully" does not appear

Spoiler

Errors (2x) in splitting the install.wim -- 1 Install.swm (1.38 GB)

Spoiler

Update:
I am wondering if splitting the Install.wim is worth it when we already got around that by creating a FAT32 and NTFS partition. It keeps on having errors.
Even Akeo (Rufus) is against it because it takes a lot of time and possibly cause errors which users are not going to be happy about

 

What about this?
https://forums.mydigitallife.net/th...tall-wim-over-4-gb.79268/page-18#post-1706187