diff --git a/os/hal/platforms/STM32/can_lld.c b/os/hal/platforms/STM32/can_lld.c
index 7dab31faf..382322fff 100644
--- a/os/hal/platforms/STM32/can_lld.c
+++ b/os/hal/platforms/STM32/can_lld.c
@@ -569,7 +569,8 @@ bool_t can_lld_is_rx_nonempty(CANDriver *canp, canmbx_t mailbox) {
 
   switch (mailbox) {
   case CAN_ANY_MAILBOX:
-    return (canp->can->RF0R & (CAN_RF0R_FMP0 | CAN_RF1R_FMP1)) != 0;
+    return ((canp->can->RF0R & CAN_RF0R_FMP0) != 0 ||
+            (canp->can->RF1R & CAN_RF1R_FMP1) != 0);
   case 1:
     return (canp->can->RF0R & CAN_RF0R_FMP0) != 0;
   case 2:
diff --git a/readme.txt b/readme.txt
index 8d20e877e..a9e3a6310 100644
--- a/readme.txt
+++ b/readme.txt
@@ -87,6 +87,7 @@
 
 *** 2.5.2 ***
 - FIX: Fixed surprising non-CRLF lines in source (bug 3607380).
+- FIX: Fixed STM32 CAN mailbox receive for second fifo (bug 3606673).
 - FIX: Fixed CAN_USE_SLEEP_MODE compilation problem (bug 3606616)(backported
   to 2.4.4)(backported to 2.2.10).
 - FIX: Fixed missing HSE bypass option for STM32F103 (bug 3606274).