diff --git a/litex/build/sim/core/modules.c b/litex/build/sim/core/modules.c
index f8d66da7a..2d12a771f 100644
--- a/litex/build/sim/core/modules.c
+++ b/litex/build/sim/core/modules.c
@@ -118,11 +118,11 @@ int litex_sim_find_ext_module(struct ext_module_list_s *first, char *name , stru
 {
   struct ext_module_list_s *list = NULL;
   int ret=RC_OK;
-  
+
   if(!first || !name || !found)
   {
     ret = RC_INVARG;
-    eprintf("Invalid arg\n");
+    eprintf("Invalid first:%s arg:%s found:%p\n", first, name, found);
     goto out;
   }
 
@@ -140,11 +140,11 @@ int litex_sim_find_module(struct module_s *first, char *name , struct module_s *
 {
   struct module_s *list = NULL;
   int ret=RC_OK;
-  
+
   if(!first || !name || !found)
   {
     ret = RC_INVARG;
-    eprintf("Invalid arg\n");
+    eprintf("Invalid first:%s arg:%s found:%p\n", first, name, found);
     goto out;
   }