diff --git a/os/common/abstractions/cmsis_os/cmsis_os.h b/os/common/abstractions/cmsis_os/cmsis_os.h
index 89cba2b5b..45cc4d9f8 100644
--- a/os/common/abstractions/cmsis_os/cmsis_os.h
+++ b/os/common/abstractions/cmsis_os/cmsis_os.h
@@ -402,7 +402,7 @@ static const msg_t os_messageQ_buf_##name[queue_sz];                        \
 static mailbox_t os_messageQ_obj_##name;                                    \
 const osMessageQDef_t os_messageQ_def_##name = {                            \
   (queue_sz),                                                               \
-  sizeof (type)                                                             \
+  sizeof (type),                                                            \
   (void *)&os_messageQ_obj_##name,                                          \
   (void *)&os_messageQ_buf_##name[0]                                        \
 }
diff --git a/readme.txt b/readme.txt
index fc680eec7..9b68177fd 100644
--- a/readme.txt
+++ b/readme.txt
@@ -152,6 +152,8 @@
 - NIL: Added STM32F7 demo.
 - VAR: Fixed missing const qualifier in local shell commands array (bug #797)
        (backported to 16.1.6, 3.0.6, 2.6.10).
+- VAR: Fixed compilation error in cmsis_os.h (bug #796)(backported to 16.1.6,
+       3.0.6).
 - HAL: Fixed double empty lines in HAL (bug #794)(backported to 16.1.6, 
        3.0.6, 2.6.10).
 - RT:  Fixed double empty lines in RT (bug #793)(backported to 16.1.6, 3.0.6).