diff --git a/components/net/lwip-1.4.1/src/arch/sys_arch.c b/components/net/lwip-1.4.1/src/arch/sys_arch.c
index 793568d836b82b0eaf14011a2fe60238478192c5..3cdb637d1545b7045e818c4e38579ceb2b3e30b7 100644
--- a/components/net/lwip-1.4.1/src/arch/sys_arch.c
+++ b/components/net/lwip-1.4.1/src/arch/sys_arch.c
@@ -515,10 +515,19 @@ u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout)
     return tick;
 }
 
-/** Wait for a new message to arrive in the mbox
+/**
+ * @ingroup sys_mbox
+ * This is similar to sys_arch_mbox_fetch, however if a message is not
+ * present in the mailbox, it immediately returns with the code
+ * SYS_MBOX_EMPTY. On success 0 is returned.
+ * To allow for efficient implementations, this can be defined as a
+ * function-like macro in sys_arch.h instead of a normal function. For
+ * example, a naive implementation could be:
+ * \#define sys_arch_mbox_tryfetch(mbox,msg) sys_arch_mbox_fetch(mbox,msg,1)
+ * although this would introduce unnecessary delays.
+ *
  * @param mbox mbox to get a message from
  * @param msg pointer where the message is stored
- * @param timeout maximum time (in milliseconds) to wait for a message
  * @return 0 (milliseconds) if a message has been received
  *         or SYS_MBOX_EMPTY if the mailbox is empty
  */
@@ -534,7 +543,7 @@ u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg)
     else
     {
         if (ret == RT_EOK)
-            ret = 1;
+            ret = 0;
     }
 
     return ret;
diff --git a/components/net/lwip-2.0.2/src/arch/sys_arch.c b/components/net/lwip-2.0.2/src/arch/sys_arch.c
index 3de85b338c510328a03d513dcb9115e6328a3d73..b779264f967df5046e9bd7b9a0a129c943b8d84a 100644
--- a/components/net/lwip-2.0.2/src/arch/sys_arch.c
+++ b/components/net/lwip-2.0.2/src/arch/sys_arch.c
@@ -526,10 +526,19 @@ u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout)
     return tick;
 }
 
-/** Wait for a new message to arrive in the mbox
+/**
+ * @ingroup sys_mbox
+ * This is similar to sys_arch_mbox_fetch, however if a message is not
+ * present in the mailbox, it immediately returns with the code
+ * SYS_MBOX_EMPTY. On success 0 is returned.
+ * To allow for efficient implementations, this can be defined as a
+ * function-like macro in sys_arch.h instead of a normal function. For
+ * example, a naive implementation could be:
+ * \#define sys_arch_mbox_tryfetch(mbox,msg) sys_arch_mbox_fetch(mbox,msg,1)
+ * although this would introduce unnecessary delays.
+ *
  * @param mbox mbox to get a message from
  * @param msg pointer where the message is stored
- * @param timeout maximum time (in milliseconds) to wait for a message
  * @return 0 (milliseconds) if a message has been received
  *         or SYS_MBOX_EMPTY if the mailbox is empty
  */
@@ -544,7 +553,7 @@ u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg)
     else
     {
         if (ret == RT_EOK)
-            ret = 1;
+            ret = 0;
     }
 
     return ret;
diff --git a/components/net/lwip-2.0.3/src/arch/sys_arch.c b/components/net/lwip-2.0.3/src/arch/sys_arch.c
index 3de85b338c510328a03d513dcb9115e6328a3d73..b779264f967df5046e9bd7b9a0a129c943b8d84a 100644
--- a/components/net/lwip-2.0.3/src/arch/sys_arch.c
+++ b/components/net/lwip-2.0.3/src/arch/sys_arch.c
@@ -526,10 +526,19 @@ u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout)
     return tick;
 }
 
-/** Wait for a new message to arrive in the mbox
+/**
+ * @ingroup sys_mbox
+ * This is similar to sys_arch_mbox_fetch, however if a message is not
+ * present in the mailbox, it immediately returns with the code
+ * SYS_MBOX_EMPTY. On success 0 is returned.
+ * To allow for efficient implementations, this can be defined as a
+ * function-like macro in sys_arch.h instead of a normal function. For
+ * example, a naive implementation could be:
+ * \#define sys_arch_mbox_tryfetch(mbox,msg) sys_arch_mbox_fetch(mbox,msg,1)
+ * although this would introduce unnecessary delays.
+ *
  * @param mbox mbox to get a message from
  * @param msg pointer where the message is stored
- * @param timeout maximum time (in milliseconds) to wait for a message
  * @return 0 (milliseconds) if a message has been received
  *         or SYS_MBOX_EMPTY if the mailbox is empty
  */
@@ -544,7 +553,7 @@ u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg)
     else
     {
         if (ret == RT_EOK)
-            ret = 1;
+            ret = 0;
     }
 
     return ret;
diff --git a/components/net/lwip-2.1.2/src/arch/sys_arch.c b/components/net/lwip-2.1.2/src/arch/sys_arch.c
index a7d3f9896878966e5d218f6c2fda60aa0c98749d..62dc4930079a60073fbe65438c5ad0c348bc02fd 100644
--- a/components/net/lwip-2.1.2/src/arch/sys_arch.c
+++ b/components/net/lwip-2.1.2/src/arch/sys_arch.c
@@ -540,10 +540,19 @@ u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout)
     return tick;
 }
 
-/** Wait for a new message to arrive in the mbox
+/**
+ * @ingroup sys_mbox
+ * This is similar to sys_arch_mbox_fetch, however if a message is not
+ * present in the mailbox, it immediately returns with the code
+ * SYS_MBOX_EMPTY. On success 0 is returned.
+ * To allow for efficient implementations, this can be defined as a
+ * function-like macro in sys_arch.h instead of a normal function. For
+ * example, a naive implementation could be:
+ * \#define sys_arch_mbox_tryfetch(mbox,msg) sys_arch_mbox_fetch(mbox,msg,1)
+ * although this would introduce unnecessary delays.
+ *
  * @param mbox mbox to get a message from
  * @param msg pointer where the message is stored
- * @param timeout maximum time (in milliseconds) to wait for a message
  * @return 0 (milliseconds) if a message has been received
  *         or SYS_MBOX_EMPTY if the mailbox is empty
  */
@@ -558,7 +567,7 @@ u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg)
     else
     {
         if (ret == RT_EOK)
-            ret = 1;
+            ret = 0;
     }
 
     return ret;