feat: Add MaxUSBDrives parameter for parallel USB drive processing

- Introduced a new parameter `MaxUSBDrives` to control the maximum number of USB drives that can be built in parallel, with a default value of 5.
- Updated UI to include a textbox for setting `MaxUSBDrives`.
- Implemented validation to ensure the value is a non-negative integer.
- Adjusted the deployment function to respect the `MaxUSBDrives` limit during USB drive creation.

FFUDevelopment/BuildFFUVM.ps1

@@ -193,6 +193,9 @@ A hashtable containing USB drives from win32_diskdrive where:
 
 Example: @{ "SanDisk Ultra" = "1234567890"; "Kingston DataTraveler" = "0987654321" }
 
+.PARAMETER MaxUSBDrives
+Maximum number of USB drives to build in parallel. Default is 5. Set to 0 to process all discovered drives (or all selected drives when USBDriveList or selection is used). Actual throttle will never exceed the number of drives discovered.
+
 .PARAMETER UserAgent
 User agent string to use when downloading files.
 
@@ -344,6 +347,7 @@ param(
     [string]$ProductKey,
     [bool]$BuildUSBDrive,
     [hashtable]$USBDriveList,
+    [int]$MaxUSBDrives = 5,
     [Parameter(Mandatory = $false)]
     [ValidateSet(10, 11, 2016, 2019, 2021, 2022, 2024, 2025)]
     [int]$WindowsRelease = 11,
@@ -3310,6 +3314,9 @@ Function New-DeploymentUSB {
     # 2. Partition and format USB drives in parallel
     WriteLog "Starting parallel creation for $USBDrivesCount USB drive(s)."
 
+    $resolvedUSBThrottle = if ($MaxUSBDrives -gt 0) { [math]::Min($MaxUSBDrives, $USBDrivesCount) } else { $USBDrivesCount }
+    WriteLog "Using USB drive throttle limit: $resolvedUSBThrottle (MaxUSBDrives param: $MaxUSBDrives; Drives to process: $USBDrivesCount)"
+
     $USBDrives | ForEach-Object -Parallel {
         $USBDrive = $_
         
@@ -3391,7 +3398,7 @@ Function New-DeploymentUSB {
         Set-Volume -DriveLetter $DeployPartition.DriveLetter -NewFileSystemLabel "Deploy"
         WriteLog "Finished processing disk $DiskNumber"
 
-    } -ThrottleLimit 2
+    } -ThrottleLimit $resolvedUSBThrottle
 
     # Dismount ISO after all parallel jobs are complete
     WriteLog "Dismounting deployment ISO."

FFUDevelopment/BuildFFUVM_UI.xaml

@@ -755,6 +755,12 @@
                                 <CheckBox x:Name="chkCopyUnattend" Content="Copy Unattend.xml" Margin="5" VerticalAlignment="Center" Tag="When set to $true, will copy the Unattend.xml file to the USB drive."/>
                                 <CheckBox x:Name="chkCopyPPKG" Content="Copy Provisioning Package" Margin="5" VerticalAlignment="Center" Tag="When set to $true, will copy the provisioning package to the USB drive."/>
 
+                                <!-- Max USB Drives -->
+                                <StackPanel Orientation="Horizontal" Margin="5">
+                                    <TextBlock Text="Max USB Drives" VerticalAlignment="Center" ToolTip="Maximum number of USB drives to build at once. Enter 0 to process all discovered (or all selected) drives."/>
+                                    <TextBox x:Name="txtMaxUSBDrives" Width="50" Margin="10,0,0,0" Text="5" VerticalAlignment="Center" ToolTip="Maximum number of USB drives to build at once. Enter 0 to process all discovered (or all selected) drives."/>
+                                </StackPanel>
+
                                 <!-- USB Drive Selection Section -->
                                 <Grid x:Name="usbDriveSelectionPanel" Margin="5,0,0,0">
                                     <Grid.RowDefinitions>

FFUDevelopment/FFUUI.Core/FFUUI.Core.Config.psm1

@@ -93,6 +93,7 @@ function Get-UIConfig {
         USBDriveList                   = @{}
         Username                       = $State.Controls.txtUsername.Text
         Threads                        = [int]$State.Controls.txtThreads.Text
+        MaxUSBDrives                   = [int]$State.Controls.txtMaxUSBDrives.Text
         Verbose                        = $State.Controls.chkVerbose.IsChecked
         VMHostIPAddress                = $State.Controls.txtVMHostIPAddress.Text
         VMLocation                     = $State.Controls.txtVMLocation.Text
@@ -277,6 +278,7 @@ function Update-UIFromConfig {
     Set-UIValue -ControlName 'txtShareName' -PropertyName 'Text' -ConfigObject $ConfigContent -ConfigKey 'ShareName' -State $State
     Set-UIValue -ControlName 'txtUsername' -PropertyName 'Text' -ConfigObject $ConfigContent -ConfigKey 'Username' -State $State
     Set-UIValue -ControlName 'txtThreads' -PropertyName 'Text' -ConfigObject $ConfigContent -ConfigKey 'Threads' -State $State
+    Set-UIValue -ControlName 'txtMaxUSBDrives' -PropertyName 'Text' -ConfigObject $ConfigContent -ConfigKey 'MaxUSBDrives' -State $State
     Set-UIValue -ControlName 'chkBuildUSBDriveEnable' -PropertyName 'IsChecked' -ConfigObject $ConfigContent -ConfigKey 'BuildUSBDrive' -State $State
     Set-UIValue -ControlName 'chkCompactOS' -PropertyName 'IsChecked' -ConfigObject $ConfigContent -ConfigKey 'CompactOS' -State $State
     Set-UIValue -ControlName 'chkUpdateADK' -PropertyName 'IsChecked' -ConfigObject $ConfigContent -ConfigKey 'UpdateADK' -State $State

FFUDevelopment/FFUUI.Core/FFUUI.Core.Handlers.psm1

@@ -44,7 +44,8 @@ function Register-EventHandlers {
         $State.Controls.txtDiskSize,
         $State.Controls.txtMemory,
         $State.Controls.txtProcessors,
-        $State.Controls.txtThreads
+        $State.Controls.txtThreads,
+        $State.Controls.txtMaxUSBDrives
     )
 
     # Attach the handlers to each relevant textbox
@@ -72,6 +73,20 @@ function Register-EventHandlers {
             })
     }
 
+    # Add specific validation for the Max USB Drives textbox to ensure it's an integer >=0 (allow 0 meaning all)
+    if ($null -ne $State.Controls.txtMaxUSBDrives) {
+        $State.Controls.txtMaxUSBDrives.Add_LostFocus({
+                param($eventSource, $routedEventArgs)
+                $textBox = $eventSource
+                $currentValue = 0
+                $isValidInteger = [int]::TryParse($textBox.Text, [ref]$currentValue)
+                if (-not $isValidInteger -or $currentValue -lt 0) {
+                    $textBox.Text = '0'
+                    WriteLog "Max USB Drives value was invalid or less than 0. Reset to 0 (process all)."
+                }
+            })
+    }
+
     # Build Tab Event Handlers
     $State.Controls.btnBrowseFFUDevPath.Add_Click({
             param($eventSource, $routedEventArgs)

FFUDevelopment/FFUUI.Core/FFUUI.Core.Initialize.psm1

@@ -115,6 +115,7 @@ function Initialize-UIControls {
     $State.Controls.txtShareName = $window.FindName('txtShareName')
     $State.Controls.txtUsername = $window.FindName('txtUsername')
     $State.Controls.txtThreads = $window.FindName('txtThreads')
+    $State.Controls.txtMaxUSBDrives = $window.FindName('txtMaxUSBDrives')
     $State.Controls.chkCompactOS = $window.FindName('chkCompactOS')
     $State.Controls.chkOptimize = $window.FindName('chkOptimize')
     $State.Controls.chkAllowVHDXCaching = $window.FindName('chkAllowVHDXCaching')
@@ -227,6 +228,7 @@ function Initialize-UIDefaults {
     $State.Controls.txtShareName.Text = $State.Defaults.generalDefaults.ShareName
     $State.Controls.txtUsername.Text = $State.Defaults.generalDefaults.Username
     $State.Controls.txtThreads.Text = $State.Defaults.generalDefaults.Threads
+    $State.Controls.txtMaxUSBDrives.Text = $State.Defaults.generalDefaults.MaxUSBDrives
     $State.Controls.chkBuildUSBDriveEnable.IsChecked = $State.Defaults.generalDefaults.BuildUSBDriveEnable
     $State.Controls.chkCompactOS.IsChecked = $State.Defaults.generalDefaults.CompactOS
     $State.Controls.chkUpdateADK.IsChecked = $State.Defaults.generalDefaults.UpdateADK

FFUDevelopment/FFUUI.Core/FFUUI.Core.psm1

@@ -117,6 +117,7 @@ function Get-GeneralDefaults {
         ShareName                      = "FFUCaptureShare"
         Username                       = "ffu_user"
         Threads                        = 5
+        MaxUSBDrives                   = 5
         BuildUSBDriveEnable            = $false
         CompactOS                      = $true
         Optimize                       = $true