diff --git a/cli/release_package.php b/cli/release_package.php
index c5f83f4..48aadd1 100644
--- a/cli/release_package.php
+++ b/cli/release_package.php
@@ -250,6 +250,14 @@ class ReleasePackageCli extends CliFramework
                 }
                 $subZipPath = "{$outputDir}/{$subName}.zip";
 
+                // Use pre-built ZIP if staged in the output directory
+                if (file_exists($subZipPath) && filesize($subZipPath) > 0) {
+                    $zip->addFile($subZipPath, "packages/{$subName}.zip");
+                    $sizeKb = number_format(filesize($subZipPath) / 1024, 1);
+                    echo "  Sub-package: {$subName}.zip (pre-built, {$sizeKb} KB)\n";
+                    continue;
+                }
+
                 // If sub-package is a full repo checkout (e.g. git submodule),
                 // look for a source/ or src/ subdirectory containing a Joomla manifest XML
                 // and zip that instead of the repo root.
@@ -270,6 +278,16 @@ class ReleasePackageCli extends CliFramework
                     }
                 }
 
+                // If source dir has no manifest, the submodule may be empty.
+                // Try to download the pre-built release from Gitea.
+                $hasManifest = !empty(glob("{$subSourceDir}/*.xml") ?: []);
+                if (!$hasManifest && $token !== '' && $this->downloadSubmoduleRelease($root, $subName, $subZipPath, $token)) {
+                    $zip->addFile($subZipPath, "packages/{$subName}.zip");
+                    $sizeKb = number_format(filesize($subZipPath) / 1024, 1);
+                    echo "  Sub-package: {$subName}.zip (downloaded release, {$sizeKb} KB)\n";
+                    continue;
+                }
+
                 $subZip = new \ZipArchive();
                 if ($subZip->open($subZipPath, \ZipArchive::CREATE | \ZipArchive::OVERWRITE) !== true) {
                     $this->log('ERROR', "Failed to create sub-package ZIP: {$subZipPath}");
@@ -527,6 +545,103 @@ class ReleasePackageCli extends CliFramework
         return false;
     }
 
+    /**
+     * Download a pre-built release ZIP for a sub-package that is a git submodule
+     * with an empty or missing source directory.
+     *
+     * Reads .gitmodules to find the submodule's remote URL, derives the Gitea
+     * API path, and downloads the latest stable release asset.
+     */
+    private function downloadSubmoduleRelease(string $root, string $subName, string $destPath, string $token): bool
+    {
+        $gitmodulesPath = "{$root}/.gitmodules";
+        if (!file_exists($gitmodulesPath)) {
+            return false;
+        }
+
+        $gitmodules = file_get_contents($gitmodulesPath);
+        if ($gitmodules === false) {
+            return false;
+        }
+
+        // Find the submodule URL by matching the subName in the path
+        if (!preg_match('/\[submodule\s[^\]]*\]\s*\n\s*path\s*=\s*[^\n]*' . preg_quote($subName, '/') . '\s*\n\s*url\s*=\s*(\S+)/m', $gitmodules, $matches)) {
+            return false;
+        }
+
+        $remoteUrl = preg_replace('/\.git$/', '', $matches[1]);
+
+        // Extract org/repo from the URL
+        if (!preg_match('#[/:]([^/]+)/([^/]+)$#', $remoteUrl, $parts)) {
+            return false;
+        }
+
+        $org  = $parts[1];
+        $repo = $parts[2];
+
+        // Derive the Gitea API base from the remote URL
+        $parsed = parse_url($remoteUrl);
+        $scheme = $parsed['scheme'] ?? 'https';
+        $host   = $parsed['host'] ?? '';
+        if ($host === '') {
+            return false;
+        }
+        $apiBase = "{$scheme}://{$host}/api/v1/repos/{$org}/{$repo}";
+
+        echo "  Submodule {$subName}: source empty, downloading release from {$org}/{$repo}...\n";
+
+        // Get the stable release
+        $result = $this->giteaApiRequest("{$apiBase}/releases/tags/stable", $token);
+        if ($result['data'] === null || !isset($result['data']['assets'])) {
+            echo "  WARNING: No stable release found for {$org}/{$repo}\n";
+            return false;
+        }
+
+        // Find the ZIP asset (not .sha256)
+        $downloadUrl = '';
+        foreach ($result['data']['assets'] as $asset) {
+            if (!is_array($asset)) {
+                continue;
+            }
+            $name = $asset['name'] ?? '';
+            if (str_ends_with($name, '.zip') && !str_ends_with($name, '.sha256')) {
+                $downloadUrl = $asset['browser_download_url'] ?? '';
+                break;
+            }
+        }
+
+        if ($downloadUrl === '') {
+            echo "  WARNING: No ZIP asset in {$org}/{$repo} stable release\n";
+            return false;
+        }
+
+        // Download the ZIP
+        $ch = curl_init($downloadUrl);
+        if ($ch === false) {
+            return false;
+        }
+        curl_setopt_array($ch, [
+            CURLOPT_RETURNTRANSFER => true,
+            CURLOPT_FOLLOWLOCATION => true,
+            CURLOPT_HTTPHEADER => ["Authorization: token {$token}"],
+            CURLOPT_TIMEOUT => 120,
+        ]);
+        $content = curl_exec($ch);
+        $httpCode = (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
+        curl_close($ch);
+
+        if ($httpCode < 200 || $httpCode >= 300 || !is_string($content) || $content === '') {
+            echo "  WARNING: Download failed (HTTP {$httpCode})\n";
+            return false;
+        }
+
+        if (file_put_contents($destPath, $content) === false) {
+            return false;
+        }
+
+        return true;
+    }
+
     /**
      * Recursively add files from a directory to a ZipArchive.
      */