diff --git a/features/FEATURE_LWIP/TESTS/mbedmicro-net/tcp_echo_parallel/main.cpp b/features/FEATURE_LWIP/TESTS/mbedmicro-net/tcp_echo_parallel/main.cpp
index bc42ca885f..762babb704 100644
--- a/features/FEATURE_LWIP/TESTS/mbedmicro-net/tcp_echo_parallel/main.cpp
+++ b/features/FEATURE_LWIP/TESTS/mbedmicro-net/tcp_echo_parallel/main.cpp
@@ -64,7 +64,7 @@ public:
         TEST_ASSERT_EQUAL(0, err);
 
         iomutex.lock();
-        printf("HTTP: Connected to %s:%d\r\n", 
+        printf("HTTP: Connected to %s:%d\r\n",
                 tcp_addr.get_ip_address(), tcp_addr.get_port());
         printf("tx_buffer buffer size: %u\r\n", sizeof(tx_buffer));
         printf("rx_buffer buffer size: %u\r\n", sizeof(rx_buffer));
@@ -85,7 +85,8 @@ public:
 };
 
 int main() {
-    GREENTEA_SETUP(60, "tcp_echo");
+    char uuid[48] = {0};
+    GREENTEA_SETUP_UUID(60, "tcp_echo", uuid, 48);
 
     Echo echoers[MBED_CFG_TCP_CLIENT_ECHO_THREADS];
 
diff --git a/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo/main.cpp b/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo/main.cpp
index 0cd678fced..8441a2e528 100644
--- a/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo/main.cpp
+++ b/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo/main.cpp
@@ -83,10 +83,23 @@ int main() {
         while (success < ECHO_LOOPS) {
             prep_buffer(uuid, uuid_len, tx_buffer, sizeof(tx_buffer));
             const int ret = sock.sendto(udp_addr, tx_buffer, sizeof(tx_buffer));
-            printf("[%02d] sent %d Bytes - %.*s  \n", i, ret, MBED_CFG_UDP_CLIENT_ECHO_BUFFER_SIZE, tx_buffer);
+            if (ret >= 0) {
+                printf("[%02d] sent %d Bytes - %.*s  \n", i, ret, ret, tx_buffer);
+            } else {
+                printf("[%02d] Network error %d\n", i, ret);
+                i++;
+                continue;
+            }
+
             SocketAddress temp_addr;
             const int n = sock.recvfrom(&temp_addr, rx_buffer, sizeof(rx_buffer));
-            printf("[%02d] recv %d Bytes - %.*s  \n", i, ret, MBED_CFG_UDP_CLIENT_ECHO_BUFFER_SIZE, rx_buffer);
+            if (n >= 0) {
+                printf("[%02d] receive %d Bytes - %.*s  \n", i, n, n, tx_buffer);
+            } else {
+                printf("[%02d] Network error %d\n", i, n);
+                i++;
+                continue;
+            }
 
             if ((temp_addr == udp_addr &&
                  n == sizeof(tx_buffer) &&
diff --git a/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo_parallel/main.cpp b/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo_parallel/main.cpp
index 39366dff6e..6332a1d40d 100644
--- a/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo_parallel/main.cpp
+++ b/features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_echo_parallel/main.cpp
@@ -90,15 +90,31 @@ public:
         while(success < ECHO_LOOPS) {
             prep_buffer(id, uuid_buffer, uuid_len, tx_buffer, sizeof(tx_buffer));
             const int ret = sock.sendto(udp_addr, tx_buffer, sizeof(tx_buffer));
-            iomutex.lock();
-            printf("[ID:%01d][%02d] sent %d Bytes - %.*s\n", id, i, ret, MBED_CFG_UDP_CLIENT_ECHO_BUFFER_SIZE, tx_buffer);
-            iomutex.unlock();
+            if (ret >= 0) {
+                iomutex.lock();
+                printf("[ID:%01d][%02d] sent %d Bytes - %.*s  \n", id, i, ret, ret, tx_buffer);
+                iomutex.unlock();
+            } else {
+                iomutex.lock();
+                printf("[ID:%01d][%02d] Network error %d\n", id, i, ret);
+                iomutex.unlock();
+                i++;
+                continue;
+            }
 
             SocketAddress temp_addr;
             const int n = sock.recvfrom(&temp_addr, rx_buffer, sizeof(rx_buffer));
-            iomutex.lock();
-            printf("[ID:%01d][%02d] recv %d Bytes - %.*s\n", id, i, ret, MBED_CFG_UDP_CLIENT_ECHO_BUFFER_SIZE, rx_buffer);
-            iomutex.unlock();
+            if (n >= 0) {
+                iomutex.lock();
+                printf("[ID:%01d][%02d] receive %d Bytes - %.*s  \n", id, i, n, n, tx_buffer);
+                iomutex.unlock();
+            } else {
+                iomutex.lock();
+                printf("[ID:%01d][%02d] Network error %d\n", id, i, n);
+                iomutex.unlock();
+                i++;
+                continue;
+            }
 
             if ((temp_addr == udp_addr &&
                  n == sizeof(tx_buffer) &&