diff --git a/fwprovider/cluster/sdn/zone/resource_generic.go b/fwprovider/cluster/sdn/zone/resource_generic.go
index 3c4e9005..94efe910 100644
--- a/fwprovider/cluster/sdn/zone/resource_generic.go
+++ b/fwprovider/cluster/sdn/zone/resource_generic.go
@@ -68,16 +68,9 @@ func (m *genericModel) getID() string {
 	return m.ID.ValueString()
 }
 
-func genericAttributesWith(extraAttributes ...map[string]schema.Attribute) map[string]schema.Attribute {
-	if len(extraAttributes) > 1 {
-		panic("genericAttributesWith expects at most one extraAttributes map")
-	}
-
-	if len(extraAttributes) == 0 {
-		extraAttributes = append(extraAttributes, make(map[string]schema.Attribute))
-	}
-
-	maps.Copy(extraAttributes[0], map[string]schema.Attribute{
+func genericAttributesWith(extraAttributes map[string]schema.Attribute) map[string]schema.Attribute {
+	// Start with generic attributes as the base
+	result := map[string]schema.Attribute{
 		"dns": schema.StringAttribute{
 			Optional:    true,
 			Description: "DNS API server address.",
@@ -116,9 +109,14 @@ func genericAttributesWith(extraAttributes ...map[string]schema.Attribute) map[s
 			Optional:    true,
 			Description: "Reverse DNS API server address.",
 		},
-	})
+	}
 
-	return extraAttributes[0]
+	// Add extra attributes, allowing them to override generic ones if needed
+	if extraAttributes != nil {
+		maps.Copy(result, extraAttributes)
+	}
+
+	return result
 }
 
 type zoneModel interface {
diff --git a/fwprovider/cluster/sdn/zone/resource_simple.go b/fwprovider/cluster/sdn/zone/resource_simple.go
index d8de0ae5..71866b7d 100644
--- a/fwprovider/cluster/sdn/zone/resource_simple.go
+++ b/fwprovider/cluster/sdn/zone/resource_simple.go
@@ -44,7 +44,7 @@ func (r *SimpleResource) Schema(_ context.Context, _ resource.SchemaRequest, res
 		MarkdownDescription: "Simple Zone in Proxmox SDN. It will create an isolated VNet bridge. " +
 			"This bridge is not linked to a physical interface, and VM traffic is only local on each the node. " +
 			"It can be used in NAT or routed setups.",
-		Attributes: genericAttributesWith(),
+		Attributes: genericAttributesWith(nil),
 	}
 }