diff --git a/client/experimental_lib/example_c/02run_test.sh b/client/experimental_lib/example_c/02run_test.sh
index a3e4ec057..7da0e3700 100755
--- a/client/experimental_lib/example_c/02run_test.sh
+++ b/client/experimental_lib/example_c/02run_test.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 
-LD_LIBRARY_PATH=../build ./test
+LD_LIBRARY_PATH=../build ./test /dev/ttyACM0
diff --git a/client/experimental_lib/example_c/02run_test_grab.sh b/client/experimental_lib/example_c/02run_test_grab.sh
index 2dd6f892b..93545c422 100755
--- a/client/experimental_lib/example_c/02run_test_grab.sh
+++ b/client/experimental_lib/example_c/02run_test_grab.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
 
-LD_LIBRARY_PATH=../build ./test_grab
+LD_LIBRARY_PATH=../build ./test_grab /dev/ttyACM0
diff --git a/client/experimental_lib/example_c/test.c b/client/experimental_lib/example_c/test.c
index a3cf212dc..319b6b08e 100644
--- a/client/experimental_lib/example_c/test.c
+++ b/client/experimental_lib/example_c/test.c
@@ -1,8 +1,14 @@
+#include <stdio.h>
+#include <stdlib.h>
 #include "pm3.h"
 
 int main(int argc, char *argv[]) {
+    if (argc < 2) {
+        printf("Usage: %s <port>\n", argv[0]);
+        exit(-1);
+    }
     pm3 *p;
-    p = pm3_open("/dev/ttyACM0");
+    p = pm3_open(argv[1]);
     pm3_console(p, "hw status");
     pm3_close(p);
 }
diff --git a/client/experimental_lib/example_c/test_grab.c b/client/experimental_lib/example_c/test_grab.c
index f4a6c64bf..c785361ba 100644
--- a/client/experimental_lib/example_c/test_grab.c
+++ b/client/experimental_lib/example_c/test_grab.c
@@ -10,6 +10,11 @@ int main(int argc, char *argv[]) {
     char buf[8196 + 1];
     size_t n;
 
+    if (argc < 2) {
+        printf("Usage: %s <port>\n", argv[0]);
+        exit(-1);
+    }
+
     if (pipe(pipefd) == -1) {
         exit(-1);
     }
@@ -31,8 +36,7 @@ int main(int argc, char *argv[]) {
         close(pipefd[1]);  // Close original write end
 
         pm3 *p;
-        p = pm3_open("/dev/ttyS9");
-        //printf("Device: %s\n", pm3_name_get(p));
+        p = pm3_open(argv[1]);
 
         // Execute the command
         pm3_console(p, "hw status");
@@ -55,6 +59,9 @@ int main(int argc, char *argv[]) {
             } else {
                 // null termination
                 buf[n] = 0;
+                if (strstr(buf, "ERROR") != NULL) {
+                    printf("%s", buf);
+                }
                 if (strstr(buf, "Unique ID") != NULL) {
                     printf("%s", buf);
                 }