diff --git a/targets/TARGET_STM/TARGET_STM32F0/can_api.c b/targets/TARGET_STM/TARGET_STM32F0/can_api.c
index d8938fca7d..0f93832791 100644
--- a/targets/TARGET_STM/TARGET_STM32F0/can_api.c
+++ b/targets/TARGET_STM/TARGET_STM32F0/can_api.c
@@ -267,10 +267,10 @@ int can_read(can_t *obj, CAN_Message *msg, int handle)
     /* Release the FIFO */
     if (handle == CAN_FIFO0) {
         /* Release FIFO0 */
-        can->RF0R = CAN_RF0R_RFOM0;
+        can->RF0R |= CAN_RF0R_RFOM0;
     } else { /* FIFONumber == CAN_FIFO1 */
       /* Release FIFO1 */
-      can->RF1R = CAN_RF1R_RFOM1;
+      can->RF1R |= CAN_RF1R_RFOM1;
     }
 
     return 1;
diff --git a/targets/TARGET_STM/TARGET_STM32F1/can_api.c b/targets/TARGET_STM/TARGET_STM32F1/can_api.c
index 2b16c47953..cbcc9ca636 100644
--- a/targets/TARGET_STM/TARGET_STM32F1/can_api.c
+++ b/targets/TARGET_STM/TARGET_STM32F1/can_api.c
@@ -270,10 +270,10 @@ int can_read(can_t *obj, CAN_Message *msg, int handle)
     /* Release the FIFO */
     if(handle == CAN_FIFO0) {
         /* Release FIFO0 */
-        can->RF0R = CAN_RF0R_RFOM0;
+        can->RF0R |= CAN_RF0R_RFOM0;
     } else { /* FIFONumber == CAN_FIFO1 */
       /* Release FIFO1 */
-      can->RF1R = CAN_RF1R_RFOM1;
+      can->RF1R |= CAN_RF1R_RFOM1;
     }
 
     return 1;
diff --git a/targets/TARGET_STM/TARGET_STM32F2/can_api.c b/targets/TARGET_STM/TARGET_STM32F2/can_api.c
index e1097e2d2b..d20e24011b 100644
--- a/targets/TARGET_STM/TARGET_STM32F2/can_api.c
+++ b/targets/TARGET_STM/TARGET_STM32F2/can_api.c
@@ -280,10 +280,10 @@ int can_read(can_t *obj, CAN_Message *msg, int handle)
     /* Release the FIFO */
     if (handle == CAN_FIFO0) {
         /* Release FIFO0 */
-        can->RF0R = CAN_RF0R_RFOM0;
+        can->RF0R |= CAN_RF0R_RFOM0;
     } else { /* FIFONumber == CAN_FIFO1 */
         /* Release FIFO1 */
-        can->RF1R = CAN_RF1R_RFOM1;
+        can->RF1R |= CAN_RF1R_RFOM1;
     }
 
     return 1;
diff --git a/targets/TARGET_STM/TARGET_STM32F3/can_api.c b/targets/TARGET_STM/TARGET_STM32F3/can_api.c
index 7bccf28639..15309dd170 100644
--- a/targets/TARGET_STM/TARGET_STM32F3/can_api.c
+++ b/targets/TARGET_STM/TARGET_STM32F3/can_api.c
@@ -270,10 +270,10 @@ int can_read(can_t *obj, CAN_Message *msg, int handle)
     /* Release the FIFO */
     if(handle == CAN_FIFO0) {
         /* Release FIFO0 */
-        can->RF0R = CAN_RF0R_RFOM0;
+        can->RF0R |= CAN_RF0R_RFOM0;
     } else { /* FIFONumber == CAN_FIFO1 */
       /* Release FIFO1 */
-      can->RF1R = CAN_RF1R_RFOM1;
+      can->RF1R |= CAN_RF1R_RFOM1;
     }
 
     return 1;
diff --git a/targets/TARGET_STM/TARGET_STM32F4/can_api.c b/targets/TARGET_STM/TARGET_STM32F4/can_api.c
index 1bad14ac5d..dbadf01597 100644
--- a/targets/TARGET_STM/TARGET_STM32F4/can_api.c
+++ b/targets/TARGET_STM/TARGET_STM32F4/can_api.c
@@ -283,10 +283,10 @@ int can_read(can_t *obj, CAN_Message *msg, int handle)
     /* Release the FIFO */
     if(handle == CAN_FIFO0) {
         /* Release FIFO0 */
-        can->RF0R = CAN_RF0R_RFOM0;
+        can->RF0R |= CAN_RF0R_RFOM0;
     } else { /* FIFONumber == CAN_FIFO1 */
       /* Release FIFO1 */
-      can->RF1R = CAN_RF1R_RFOM1;
+      can->RF1R |= CAN_RF1R_RFOM1;
     }
 
     return 1;
diff --git a/targets/TARGET_STM/TARGET_STM32F7/can_api.c b/targets/TARGET_STM/TARGET_STM32F7/can_api.c
index 7c4cac4010..73ddf859e5 100644
--- a/targets/TARGET_STM/TARGET_STM32F7/can_api.c
+++ b/targets/TARGET_STM/TARGET_STM32F7/can_api.c
@@ -283,10 +283,10 @@ int can_read(can_t *obj, CAN_Message *msg, int handle)
     /* Release the FIFO */
     if(handle == CAN_FIFO0) {
         /* Release FIFO0 */
-        can->RF0R = CAN_RF0R_RFOM0;
+        can->RF0R |= CAN_RF0R_RFOM0;
     } else { /* FIFONumber == CAN_FIFO1 */
       /* Release FIFO1 */
-      can->RF1R = CAN_RF1R_RFOM1;
+      can->RF1R |= CAN_RF1R_RFOM1;
     }
 
     return 1;
diff --git a/targets/TARGET_STM/TARGET_STM32L4/can_api.c b/targets/TARGET_STM/TARGET_STM32L4/can_api.c
index 363cfe245f..bf6ad70949 100644
--- a/targets/TARGET_STM/TARGET_STM32L4/can_api.c
+++ b/targets/TARGET_STM/TARGET_STM32L4/can_api.c
@@ -270,10 +270,10 @@ int can_read(can_t *obj, CAN_Message *msg, int handle)
     /* Release the FIFO */
     if(handle == CAN_FIFO0) {
         /* Release FIFO0 */
-        can->RF0R = CAN_RF0R_RFOM0;
+        can->RF0R |= CAN_RF0R_RFOM0;
     } else { /* FIFONumber == CAN_FIFO1 */
       /* Release FIFO1 */
-      can->RF1R = CAN_RF1R_RFOM1;
+      can->RF1R |= CAN_RF1R_RFOM1;
     }
 
     return 1;