diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index 18b60cc..a0adb9e 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -622,7 +622,7 @@ public function handle(Request $request, $type = self::MASTER_REQUEST, $catch =
       // installed yet (i.e., if no $databases array has been defined in the
       // settings.php file) and we are not already installing.
       if (!Database::getConnectionInfo() && !drupal_installation_attempted() && PHP_SAPI !== 'cli') {
-        $response = new RedirectResponse($request->getBasePath() . '/core/install.php');
+        $response = new RedirectResponse($request->getBasePath() . '/core/install.php', 302, ['Cache-Control' => 'no-cache']);
       }
       else {
         $this->boot();
@@ -668,7 +668,7 @@ protected function handleException(\Exception $e, $request, $type) {
     }
 
     if (PHP_SAPI !== 'cli' && $this->isNotInstalledException($e)) {
-      return new RedirectResponse($request->getBasePath() . '/core/install.php');
+      return new RedirectResponse($request->getBasePath() . '/core/install.php', 302, ['Cache-Control' => 'no-cache']);
     }
 
     throw $e;
@@ -689,16 +689,22 @@ protected function isNotInstalledException(\Exception $e) {
       return FALSE;
     }
 
+    // If we're already in the installer, don't worry about Drupal not being
+    // installed.
+    if (drupal_installation_attempted()) {
+      return FALSE;
+    }
+
     // Code 1049 is "missing database".
     if ($e->getCode() == 1049) {
       return TRUE;
     }
 
-    // This weird set of conditions is how we detect that the error was the
-    // sessions table was missing, which indicates an uninstalled Drupal.
-    if ($e->getCode() == 0
-        && strpos($e->getMessage(), 'SQLSTATE[42S02]') !== FALSE
-        && strpos($e->getMessage(), 'sessions') !== FALSE) {
+    // SQLSTATE[42S02] indicates a missing table. Since we should only get here
+    // in case a bootstrap step failed, we assume that whatever table is missing
+    // is missing because the installation is broken, incomplete, or not even
+    // started.
+    if ($e->getCode() == 0 && strpos($e->getMessage(), 'SQLSTATE[42S02]') !== FALSE) {
       return TRUE;
     }