diff --git a/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.c b/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.c
index c3bfe1f28..a324673a2 100644
--- a/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.c
+++ b/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.c
@@ -532,7 +532,7 @@ void sio_lld_serve_interrupt(SIODriver *siop) {
 #if SIO_USE_SYNCHRONIZATION
       /* The idle flag is forcibly cleared when an RX error event is
          detected.*/
-      imsc &= ~UART_UARTIMSC_RTIM;
+      u->UARTICR = UART_UARTICR_RTIC;
 #endif
 
       /* Disabling event sources.*/
@@ -564,7 +564,7 @@ void sio_lld_serve_interrupt(SIODriver *siop) {
 #if SIO_USE_SYNCHRONIZATION
       /* The idle flag is forcibly cleared when an RX data event is
          detected.*/
-      imsc &= ~UART_UARTIMSC_RTIM;
+      u->UARTICR = UART_UARTICR_RTIC;
 #endif
 
       /* Called once then the interrupt source is disabled.*/
diff --git a/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.h b/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.h
index cadaccc84..229a383a4 100644
--- a/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.h
+++ b/os/hal/ports/RP/LLD/UARTv1/hal_sio_lld.h
@@ -149,7 +149,8 @@
  *
  * @notapi
  */
-#define sio_lld_is_rx_idle(siop) true
+#define sio_lld_is_rx_idle(siop)                                            \
+  (bool)(((siop)->uart->UARTRIS & UART_UARTRIS_RTRIS) != 0U)
 
 /**
  * @brief   Determines if RX has pending error events to be read and cleared.