diff --git a/src/iotjs_util.c b/src/iotjs_util.c
index 598d8649f2..be0e78f9fd 100644
--- a/src/iotjs_util.c
+++ b/src/iotjs_util.c
@@ -27,7 +27,10 @@
 
 iotjs_string_t iotjs_file_read(const char* path) {
   FILE* file = fopen(path, "rb");
-  IOTJS_ASSERT(file != NULL);
+  if (file == NULL) {
+    iotjs_string_t empty_content = iotjs_string_create();
+    return empty_content;
+  }
 
   fseek(file, 0, SEEK_END);
   long ftell_ret = ftell(file);
diff --git a/src/platform/linux/iotjs_module_pwm-linux.c b/src/platform/linux/iotjs_module_pwm-linux.c
index bfca967273..1b1d8137da 100644
--- a/src/platform/linux/iotjs_module_pwm-linux.c
+++ b/src/platform/linux/iotjs_module_pwm-linux.c
@@ -140,7 +140,7 @@ bool iotjs_pwm_set_period(iotjs_pwm_t* pwm) {
       if (snprintf(buf, sizeof(buf), "%d", value) > 0) {
         result = iotjs_systemio_open_write_close(devicePath, buf);
       }
-      free(devicePath);
+      iotjs_buffer_release(devicePath);
     }
   }
   return result;
@@ -169,7 +169,7 @@ bool iotjs_pwm_set_dutycycle(iotjs_pwm_t* pwm) {
       }
 
       result = iotjs_systemio_open_write_close(devicePath, buf);
-      free(devicePath);
+      iotjs_buffer_release(devicePath);
     }
   }
   return result;
@@ -195,7 +195,7 @@ bool iotjs_pwm_set_enable(iotjs_pwm_t* pwm) {
     }
 
     result = iotjs_systemio_open_write_close(devicePath, buf);
-    free(devicePath);
+    iotjs_buffer_release(devicePath);
   }
   return result;
 }