diff --git a/libcpu/arm/stm32/context_rvds.S b/libcpu/arm/stm32/context_rvds.S
index 23e1a70142..65818909db 100644
--- a/libcpu/arm/stm32/context_rvds.S
+++ b/libcpu/arm/stm32/context_rvds.S
@@ -91,8 +91,12 @@ rt_hw_pend_sv	PROC
 	MRS		r2, PRIMASK
 	CPSID   I
 
-	; clear rt_thread_switch_interrput_flag to 0
+	; get rt_thread_switch_interrupt_flag
 	LDR		r0, =rt_thread_switch_interrput_flag
+	LDR		r1, [r0]
+	CBZ		r1, pendsv_exit			; pendsv already handled
+
+	; clear rt_thread_switch_interrput_flag to 0
 	MOV		r1, #0x00
 	STR		r1, [r0]
 
@@ -103,6 +107,7 @@ rt_hw_pend_sv	PROC
 	MRS     r1, psp                 ; get from thread stack pointer
 	STMFD	r1!, {r4 - r11}			; push r4 - r11 register
 	LDR		r0, [r0]
+
 	STR		r1, [r0]				; update from thread stack pointer
 
 swtich_to_thread
@@ -113,6 +118,7 @@ swtich_to_thread
 	LDMFD	r1!, {r4 - r11}			; pop r4 - r11 register
 	MSR		psp, r1					; update stack pointer
 
+pendsv_exit
 	; restore interrupt
 	MSR		PRIMASK, r2
 
@@ -123,9 +129,11 @@ swtich_to_thread
 ;/*
 ; * void rt_hw_context_switch_to(rt_uint32 to);
 ; * r0 --> to
+; * this fucntion is used to perform the first thread switch
 ; */
 rt_hw_context_switch_to    PROC
 	EXPORT rt_hw_context_switch_to
+	; set to thread
 	LDR		r1, =rt_interrupt_to_thread
 	STR		r0, [r1]
 
@@ -134,16 +142,23 @@ rt_hw_context_switch_to    PROC
 	MOV		r0, #0x0
 	STR		r0, [r1]
 
+	; set interrupt flag to 1
+	LDR 	r1, =rt_thread_switch_interrput_flag
+	MOV 	r0, #1
+	STR 	r0, [r1]
+
 	; set the PendSV exception priority
     LDR     r0, =NVIC_SYSPRI2
     LDR     r1, =NVIC_PENDSV_PRI
     STR     r1, [r0]
 
-    LDR     r0, =NVIC_INT_CTRL      ; trigger the PendSV exception (causes context switch)
+	; trigger the PendSV exception (causes context switch)
+    LDR     r0, =NVIC_INT_CTRL
     LDR     r1, =NVIC_PENDSVSET
     STR     r1, [r0]
 	
-    CPSIE   I                       ; enable interrupts at processor level
+	; enable interrupts at processor level
+    CPSIE   I
 	
 	; never reach here!
 	ENDP
diff --git a/net/lwip/src/lwipopts.h b/net/lwip/src/lwipopts.h
index c17573bb78..b31df7684f 100644
--- a/net/lwip/src/lwipopts.h
+++ b/net/lwip/src/lwipopts.h
@@ -46,6 +46,9 @@
 #define LWIP_DEBUG
 #endif
 
+/* Enable SO_RCVTIMEO processing.   */
+#define LWIP_SO_RCVTIMEO 			1
+
 /* ---------- Debug options ---------- */
 #ifdef LWIP_DEBUG
 #define SYS_DEBUG                   LWIP_DBG_OFF
@@ -142,7 +145,9 @@
    link level header. */
 #define PBUF_LINK_HLEN              16
 
-#define ETH_PAD_SIZE                    2       // default is 0
+#ifdef RT_LWIP_ETH_PAD_SIZE
+#define ETH_PAD_SIZE				RT_LWIP_ETH_PAD_SIZE
+#endif
 
 /** SYS_LIGHTWEIGHT_PROT
  * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection
diff --git a/src/device.c b/src/device.c
index cbd42cf103..83385128d5 100644
--- a/src/device.c
+++ b/src/device.c
@@ -83,6 +83,10 @@ rt_err_t rt_device_init_all()
 			{
 				rt_kprintf("init device:%s error:\n", device->parent.name);
 				rt_kprintf("error code:%d\n", result);
+			}
+			else
+			{
+				device->flag |= RT_DEVICE_FLAG_ACTIVATED;
 			}
 		}
 	}
diff --git a/src/mem.c b/src/mem.c
index d403e5a45a..e0b351e4ac 100644
--- a/src/mem.c
+++ b/src/mem.c
@@ -318,7 +318,7 @@ void *rt_malloc(rt_size_t size)
 
 #ifdef RT_USING_HOOK
 			if (rt_malloc_hook != RT_NULL)
-				rt_malloc_hook((rt_uint8_t*)mem, size);
+				rt_malloc_hook((rt_uint8_t *)mem + SIZEOF_STRUCT_MEM, size);
 #endif
 			/* return the memory data except mem struct */
 			return (rt_uint8_t *)mem + SIZEOF_STRUCT_MEM;