diff --git a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Issuer/OpenIDConnect.pm b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Issuer/OpenIDConnect.pm
index 36875dc61..f9412fdd1 100644
--- a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Issuer/OpenIDConnect.pm
+++ b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Issuer/OpenIDConnect.pm
@@ -198,8 +198,8 @@ sub run {
 "Override $_ OIDC param by value present in request parameter"
                     );
                     $oidc_request->{$_} = $request->{$_};
-                    $self->p->setHiddenFormValue( $req, $_, $request->{$_},
-                        '' );
+                    $self->p->setHiddenFormValue( $req, $_, $request->{$_}, '',
+                        0 );
                 }
             }
 
@@ -855,7 +855,8 @@ sub run {
                     $self->logger->debug( "OIDC request parameter $param: "
                           . $oidc_request->{$param} );
                     $self->p->setHiddenFormValue( $req, $param,
-                        $oidc_request->{$param}, '' );
+                        $oidc_request->{$param},
+                        '', 0 );
                 }
             }
 
diff --git a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm
index 023ec89b1..72bdf4553 100644
--- a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm
+++ b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm
@@ -636,7 +636,7 @@ sub setHiddenFormValue {
     if ( defined $val or !( $val & ~$val ) ) {
         $key = $prefix . $key;
 
-        #$val =~ s/\+/%2B/g;
+        $val = encode_base64($val) if $base64;
         $req->{portalHiddenFormValues}->{$key} = $val;
         $self->logger->debug("Store $val in hidden key $key");
     }
diff --git a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Plugins/Upgrade.pm b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Plugins/Upgrade.pm
index 42b920959..b61e276ca 100644
--- a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Plugins/Upgrade.pm
+++ b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Plugins/Upgrade.pm
@@ -76,7 +76,7 @@ sub confirm {
         $self->p->setHiddenFormValue(
             $req,
             upgrading => $self->ott->createToken,
-            ''
+            '', 0
         );    # Insert token
         return $self->p->login($req);
     }