diff --git a/cores/esp32/esp32-hal-uart.c b/cores/esp32/esp32-hal-uart.c
index ad01710a..a99adf44 100644
--- a/cores/esp32/esp32-hal-uart.c
+++ b/cores/esp32/esp32-hal-uart.c
@@ -179,7 +179,7 @@ static void uartDetachRx(uart_t* uart, uint8_t rxPin)
     if(uart == NULL) {
         return;
     }
-    pinMatrixInDetach(rxPin, false, false);
+    pinMatrixInDetach(UART_RXD_IDX(uart->num), false, false);
     uartDisableInterrupt(uart);
 }