diff --git a/lib/private/Setup.php b/lib/private/Setup.php
index 271e10d6..d21e2dd6 100644
--- a/lib/private/Setup.php
+++ b/lib/private/Setup.php
@@ -272,21 +272,22 @@ class Setup {
 			$dbType = 'sqlite3';
 		}
 
-		//generate a random salt that is used to salt the local  passwords
-		$salt = $this->random->generate(30);
-		// generate a secret
-		$secret = $this->random->generate(48);
-
 		//write the config file
 		$newConfigValues = [
-			'passwordsalt' => $salt,
-			'secret' => $secret,
 			'trusted_domains' => $trustedDomains,
 			'datadirectory' => $dataDir,
 			'dbtype' => $dbType,
 			'version' => implode('.', \OCP\Util::getVersion()),
 		];
 
+		if ($this->config->getValue('passwordsalt', null) === null) {
+			$newConfigValues['passwordsalt'] = $this->random->generate(30);
+		}
+
+		if ($this->config->getValue('secret', null) === null) {
+			$newConfigValues['secret'] = $this->random->generate(48);
+		}
+
 		if ($this->config->getValue('overwrite.cli.url', null) === null) {
 			$newConfigValues['overwrite.cli.url'] = $request->getServerProtocol() . '://' . $request->getInsecureServerHost() . \OC::$WEBROOT;
 		}