diff --git a/ue-updatelyra.ps1 b/ue-updatelyra.ps1
new file mode 100644
index 0000000..f747c35
--- /dev/null
+++ b/ue-updatelyra.ps1
@@ -0,0 +1,257 @@
+[CmdletBinding()] # Fail on unknown args
+param (
+    [string]$src,
+    [string]$dest,
+    [string]$mainbranch = "main",
+    [string]$upstreambranch = "lyra-upstream",
+    [string]$custombranch = "lyra-custom",
+    [switch]$dryrun = $false,
+    [switch]$help = $false
+)
+
+function Print-Usage {
+    Write-Output "Steve's Lyra Update Tool"
+    Write-Output "Usage:"
+    Write-Output "  ue-updatelyra.ps1 [-src:]sourcefolder [-dest:destfolder] [Options]"
+    Write-Output " "
+    Write-Output "  -src            : Source Lyra folder"
+    Write-Output "                  : Folder created by Create Project on Lyra in Marketplace"
+    Write-Output "  -dest           : Destination folder (default: current directory)"
+    Write-Output "                  : Must be root folder of your custom Lyra based project"
+    Write-Output "  -mainbranch     : Name of main branch (default main)"
+    Write-Output "  -upstreambranch : Name of branch containing pristine upstream version of Lyra (default lyra-upstream)"
+    Write-Output "                  : (MUST exist! We need to know where the pristine Lyra goes)"
+    Write-Output "  -custombranch   : Name of branch with your custom changes to Lyra (default lyra-custom)"
+    Write-Output "                  : (Will be created if missing)"
+    Write-Output "  -dryrun         : Don't perform any actual actions, just report on what you would do"
+    Write-Output "  -help           : Print this help"
+    Write-Output " "
+
+}
+
+$ErrorActionPreference = "Stop"
+
+if ($help) {
+    Print-Usage
+    Exit 0
+}
+
+if ($src.Length -eq 0) {
+    Write-Output "Error: Source directory argument is mandatory"
+    Print-Usage
+    Exit 3
+}
+
+if ($dest.Length -eq 0) {
+    $dest = "."
+    Write-Verbose "dest not specified, assuming current directory"
+}
+
+# Detect Git
+if ($dest -ne ".") { Push-Location $dest }
+$isGit = Test-Path ".git"
+if ($dest -ne ".") { Pop-Location }
+
+if (-not $isGit)
+{
+    Write-Output "Destination '$dest' is not a Git repo, cannot continue!"
+    Exit 3
+}
+# Check that source contains Lyra
+if (-not (Test-Path (Join-Path $src "LyraStarterGame.uproject")))
+{
+    Write-Output "Source folder '$src' does not contain LyraStarterGame.uproject"
+    Exit 3
+}
+# Check that destination contains Lyra
+if (-not (Test-Path (Join-Path $dest "LyraStarterGame.uproject")))
+{
+    Write-Output "Destination folder '$dest' does not contain LyraStarterGame.uproject"
+    Exit 3
+}
+# Check that source & destination are not the same (no standardise path in ps, Join-Path does it)
+if ((Join-Path (Resolve-Path $dest) "") -eq (Join-Path (Resolve-Path $src) ""))
+{
+    Write-Output "Source and destination folder point to the same location, $src"
+    Exit 3
+}
+
+# Check working copy is clean
+if ($dest -ne ".") { Push-Location $dest }
+
+if (Test-Path ".git") {
+    git diff --no-patch --exit-code
+    if ($LASTEXITCODE -ne 0) {
+        Write-Output "Working copy is not clean (unstaged changes)"
+        if ($dryrun) {
+            Write-Output "dryrun: Continuing but this will fail without -dryrun"
+        } else {
+            Exit $LASTEXITCODE
+        }
+    }
+    git diff --no-patch --cached --exit-code
+    if ($LASTEXITCODE -ne 0) {
+        Write-Output "Working copy is not clean (staged changes)"
+        if ($dryrun) {
+            Write-Output "dryrun: Continuing but this will fail without -dryrun"
+        } else {
+            Exit $LASTEXITCODE
+        }
+    }
+}
+
+
+git rev-parse --verify -q $upstreambranch > $null
+if ($LASTEXITCODE -ne 0)
+{
+    Write-Output "Missing Lyra upstream branch '$upstreambranch'"
+    Exit 3
+}
+git rev-parse --verify -q $mainbranch > $null
+if ($LASTEXITCODE -ne 0)
+{
+    Write-Output "Missing main branch '$mainbranch'"
+    Exit 3
+}
+
+
+if ($dryrun)
+{
+    Write-Output "Would have run:"
+}
+
+# Switch to lyra pristine branch
+if ($dryrun)
+{
+    Write-Output " > git checkout $upstreambranch"
+}
+else 
+{
+    git checkout $upstreambranch
+}
+
+# Check that dest contains Lyra
+if (-not (Test-Path (Join-Path $dest "LyraStarterGame.uproject")))
+{
+    Write-Output "Destination folder '$dest' does not contain LyraStarterGame.uproject after checking out $upstreambranch"
+    Exit 3
+}
+
+try {
+    # Copy Lyra source
+    # Use robocopy -mir so that we delete files that are missing in source
+
+    $argList = [System.Collections.ArrayList]@()
+    $argList.Add($src) > $null
+    $argList.Add($dest) > $null
+    # Mirror (deletes)
+    $argList.Add("/mir") > $null
+    # Allow resume
+    $argList.Add("/z") > $null
+    # Wait time for retry
+    $argList.Add("/w:3") > $null
+    # Exclude git files / dirs (do not delete because of mirroring)
+    $argList.Add("/xf") > $null
+    $argList.Add((Join-Path $dest ".gitignore")) > $null
+    $argList.Add("/xf") > $null
+    $argList.Add((Join-Path $dest ".gitattributes")) > $null
+    $argList.Add("/xf") > $null
+    $argList.Add((Join-Path $dest ".gitmodules")) > $null
+    $argList.Add("/xd") > $null
+    $argList.Add((Join-Path $dest ".git")) > $null
+    # Exclude source Intermediate, Binaries, DDC
+    $argList.Add("/xd") > $null
+    $argList.Add((Join-Path $src "Binaries")) > $null
+    $argList.Add("/xd") > $null
+    $argList.Add((Join-Path $src "Intermediate")) > $null
+    $argList.Add("/xd") > $null
+    $argList.Add((Join-Path $src "DerivedDataCache")) > $null
+
+    if ($dryrun) {
+        Write-Output " > robocopy $($argList -join " ")"
+
+    } else {            
+        $proc = Start-Process "robocopy" $argList -Wait -PassThru -NoNewWindow
+        # Robocopy can return up to value 8 for success
+        # See https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/robocopy
+        if ($proc.ExitCode -gt 8) {
+            throw "robocopy failed!"
+        }    
+    }
+
+
+    # Add & Commit changes, if any
+    if (-not $dryrun)
+    {
+        git add .
+        git diff --no-patch --cached --exit-code
+        if ($LASTEXITCODE -eq 0) {
+            Write-Output "No changes found to Lyra"
+            git checkout $mainbranch
+            Exit 0
+        }
+        git commit -m "Lyra update"
+    } 
+    else 
+    {
+        Write-Output " > git add . && git commit -m `"Lyra update`""
+    }
+
+
+    if (-not $dryrun)
+    {
+        # Merge changes into custom
+        git rev-parse --verify -q $custombranch > $null
+        if ($LASTEXITCODE -ne 0)
+        {
+            Write-Output "Creating branch '$custombranch'"
+            git checkout -b $custombranch
+        }
+        else
+        {
+            git checkout $custombranch
+            git merge $upstreambranch
+            if ($LASTEXITCODE -ne 0)
+            {
+                throw "Unable to merge $upstreambranch into $custombranch, resolve merge conflicts and finish merge into $mainbranch yourself "
+            }
+        }
+
+        # merge changes into main branch
+        git checkout $mainbranch
+        git merge $custombranch
+        if ($LASTEXITCODE -ne 0)
+        {
+            throw "Unable to merge $upstreambranch into $custombranch, resolve merge conflicts and finish merge into $mainbranch yourself "
+        }
+    
+
+    }
+    else 
+    {
+        Write-Output " > git checkout $custombranch"
+        Write-Output " > git merge $upstreambranch"
+        Write-Output " > git checkout $mainbranch"
+        Write-Output " > git merge $custombranch"
+
+    }
+
+
+
+}
+catch {
+    if ($dest -ne ".") { Pop-Location }
+    Write-Output $_.Exception.Message
+    Write-Output "~-~-~ Updating Lyra FAILED ~-~-~"
+    Exit 9
+}
+
+if ($dest -ne ".") { Pop-Location }
+Write-Output "~-~-~ Lyra Update Completed OK ~-~-~"
+
+
+
+
+
+
+