diff --git a/include/syscall.h b/include/syscall.h
index e78dc83f333..8a24cdbe463 100644
--- a/include/syscall.h
+++ b/include/syscall.h
@@ -249,7 +249,7 @@ static inline u64_t _syscall_ret64_invoke0(u32_t call_id)
 {
 	u64_t ret;
 
-	_arch_syscall_invoke1((u32_t)&ret, call_id);
+	(void)_arch_syscall_invoke1((u32_t)&ret, call_id);
 	return ret;
 }
 
@@ -257,7 +257,7 @@ static inline u64_t _syscall_ret64_invoke1(u32_t arg1, u32_t call_id)
 {
 	u64_t ret;
 
-	_arch_syscall_invoke2(arg1, (u32_t)&ret, call_id);
+	(void)_arch_syscall_invoke2(arg1, (u32_t)&ret, call_id);
 	return ret;
 }
 
@@ -266,7 +266,7 @@ static inline u64_t _syscall_ret64_invoke2(u32_t arg1, u32_t arg2,
 {
 	u64_t ret;
 
-	_arch_syscall_invoke3(arg1, arg2, (u32_t)&ret, call_id);
+	(void)_arch_syscall_invoke3(arg1, arg2, (u32_t)&ret, call_id);
 	return ret;
 }
 
diff --git a/scripts/gen_syscall_header.py b/scripts/gen_syscall_header.py
index f4a66ddfaf5..1305096a325 100755
--- a/scripts/gen_syscall_header.py
+++ b/scripts/gen_syscall_header.py
@@ -74,6 +74,8 @@ def gen_make_syscall(ret, argc, tabcount):
     tabs(tabcount)
     if (ret != Retval.VOID):
         sys.stdout.write("return (ret)")
+    else:
+        sys.stdout.write("return (void)")
     if (argc <= 6 and ret != Retval.U64):
         sys.stdout.write("_arch")
     sys.stdout.write("_syscall%s_invoke%d(" %