diff --git a/typo3/sysext/core/Classes/Core/Bootstrap.php b/typo3/sysext/core/Classes/Core/Bootstrap.php
index f470a46b807f..a270f3b172f7 100644
--- a/typo3/sysext/core/Classes/Core/Bootstrap.php
+++ b/typo3/sysext/core/Classes/Core/Bootstrap.php
@@ -606,7 +606,7 @@ protected function initializeErrorHandling()
                 $displayErrors = 1;
                 break;
             default:
-                if (!TYPO3_REQUESTTYPE_INSTALL) {
+                if (!(TYPO3_REQUESTTYPE & TYPO3_REQUESTTYPE_INSTALL)) {
                     // Throw exception if an invalid option is set.
                     throw new \RuntimeException(
                         'The option $TYPO3_CONF_VARS[SYS][displayErrors] is not set to "-1", "0" or "1".',