diff --git a/source/script.php b/source/script.php
index 241c05d3..b56a8491 100644
--- a/source/script.php
+++ b/source/script.php
@@ -39,8 +39,16 @@ class Pkg_MokowaasInstallerScript
 	 * with no default, causing INSERT failures when Joomla's package installer
 	 * creates placeholder rows before processing sub-extension manifests.
 	 */
+	/** @var array Download keys saved before Joomla wipes update sites */
+	private array $savedDownloadKeys = [];
+
 	public function preflight($type, $parent)
 	{
+		// CRITICAL: backup download keys BEFORE Joomla's installer wipes update sites.
+		// Joomla deletes and recreates #__update_sites rows from the manifest
+		// between preflight and postflight, clearing extra_query (dlid).
+		$this->savedDownloadKeys = $this->backupDownloadKeys();
+
 		try
 		{
 			$db = Factory::getDbo();
@@ -95,17 +103,14 @@ class Pkg_MokowaasInstallerScript
 		// Mark MokoWaaS extensions as protected (prevents disable/uninstall at framework level)
 		$this->protectExtensions();
 
-		// Save download keys before any update site manipulation
-		$savedKeys = $this->backupDownloadKeys();
-
 		// Migrate all Moko update server URLs to new format
 		$this->migrateUpdateServerUrls();
 
 		// Clean up stale/duplicate update sites
 		$this->cleanupStaleUpdateSites();
 
-		// Restore download keys that were wiped by cleanup/migration
-		$this->restoreDownloadKeys($savedKeys);
+		// Restore download keys saved in preflight (before Joomla wiped them)
+		$this->restoreDownloadKeys($this->savedDownloadKeys);
 
 		// Fix orphaned update records (extension_id=0)
 		$this->fixUpdateRecords();