diff --git a/tests/wsl/install/update_windows.pm b/tests/wsl/install/update_windows.pm
index 13fe0418060e..1927f03f55e0 100644
--- a/tests/wsl/install/update_windows.pm
+++ b/tests/wsl/install/update_windows.pm
@@ -17,7 +17,7 @@ sub run {
     $self->run_in_powershell(cmd => "Invoke-WebRequest -Uri \"$vbs_url\" -OutFile \"$env:TEMP\\UpdateInstall.ps1\"");
     $self->run_in_powershell(cmd => "Set-ExecutionPolicy Bypass -Scope CurrentUser -Force");
     $self->run_in_powershell(
-        cmd => '$env:TEMP\\UpdateInstall.ps1 -NonInteractive',
+        cmd => "\$env:TEMP\\UpdateInstall.ps1 -NonInteractive",
         code => sub {
             die("Update script finished unespectedly or timed out...")
               unless wait_serial('0', timeout => 3600);