diff --git a/components/drivers/serial/serial.c b/components/drivers/serial/serial.c
index f5a199e10..3bae89c74 100644
--- a/components/drivers/serial/serial.c
+++ b/components/drivers/serial/serial.c
@@ -522,12 +522,10 @@ void rt_hw_serial_isr(struct rt_serial_device *serial, int event)
             rt_base_t level;
             struct rt_serial_rx_fifo* rx_fifo;
 
+            /* interrupt mode receive */
             rx_fifo = (struct rt_serial_rx_fifo*)serial->serial_rx;
             RT_ASSERT(rx_fifo != RT_NULL);
-            
-            /* interrupt mode receive */
-            RT_ASSERT(serial->parent.open_flag & RT_DEVICE_FLAG_INT_RX);
-            
+
             while (1)
             {
                 ch = serial->ops->getc(serial);
diff --git a/components/external/lodepng/SConscript b/components/external/lodepng/SConscript
index fd05e1013..55d6d01d3 100644
--- a/components/external/lodepng/SConscript
+++ b/components/external/lodepng/SConscript
@@ -1,4 +1,5 @@
 from building import *
+import rtconfig
 
 cwd = GetCurrentDir()
 src = Split('''
@@ -7,6 +8,9 @@ lodepng.c
 
 CPPPATH = [cwd]
 
-group = DefineGroup('RTGUI', src, depend = ['RT_USING_RTGUI', 'RTGUI_IMAGE_LODEPNG', 'RT_USING_LIBC'], CPPPATH = CPPPATH)
+if rtconfig.ARCH == 'sim':
+	group = DefineGroup('RTGUI', src, depend = ['RT_USING_RTGUI', 'RTGUI_IMAGE_LODEPNG'], CPPPATH = CPPPATH)
+else:
+	group = DefineGroup('RTGUI', src, depend = ['RT_USING_RTGUI', 'RTGUI_IMAGE_LODEPNG', 'RT_USING_LIBC'], CPPPATH = CPPPATH)
 
 Return('group')
diff --git a/src/module.c b/src/module.c
index 0de93867c..b03611a4f 100644
--- a/src/module.c
+++ b/src/module.c
@@ -178,6 +178,7 @@ rt_module_t rt_module_self(void)
     /* return current module */
     return (rt_module_t)tid->module_id;
 }
+RTM_EXPORT(rt_module_self);
 
 static int rt_module_arm_relocate(struct rt_module *module,
                                   Elf32_Rel        *rel,
@@ -1563,6 +1564,7 @@ rt_module_t rt_module_find(const char *name)
     /* not found */
     return RT_NULL;
 }
+RTM_EXPORT(rt_module_find);
 
 #ifdef RT_USING_SLAB
 /*