diff --git a/components/driver/uart.c b/components/driver/uart.c
index 35cce7b349..6b4c72f06a 100644
--- a/components/driver/uart.c
+++ b/components/driver/uart.c
@@ -1025,7 +1025,6 @@ esp_err_t uart_wait_tx_done(uart_port_t uart_num, TickType_t ticks_to_wait)
         xSemaphoreGive(p_uart_obj[uart_num]->tx_mux);
         return ESP_OK;
     }
-    uart_hal_clr_intsts_mask(&(uart_context[uart_num].hal), UART_INTR_TX_DONE);
     UART_ENTER_CRITICAL(&(uart_context[uart_num].spinlock));
     uart_hal_ena_intr_mask(&(uart_context[uart_num].hal), UART_INTR_TX_DONE);
     UART_EXIT_CRITICAL(&(uart_context[uart_num].spinlock));
@@ -1039,9 +1038,7 @@ esp_err_t uart_wait_tx_done(uart_port_t uart_num, TickType_t ticks_to_wait)
     //take 2nd tx_done_sem, wait given from ISR
     res = xSemaphoreTake(p_uart_obj[uart_num]->tx_done_sem, (portTickType)ticks_to_wait);
     if (res == pdFALSE) {
-        UART_ENTER_CRITICAL(&(uart_context[uart_num].spinlock));
-        uart_hal_disable_intr_mask(&(uart_context[uart_num].hal), UART_INTR_TX_DONE);
-        UART_EXIT_CRITICAL(&(uart_context[uart_num].spinlock));
+        // The TX_DONE interrupt will be disabled in ISR
         xSemaphoreGive(p_uart_obj[uart_num]->tx_mux);
         return ESP_ERR_TIMEOUT;
     }
diff --git a/components/freemodbus/port/port.h b/components/freemodbus/port/port.h
index 06d7a28c79..5307f371fc 100644
--- a/components/freemodbus/port/port.h
+++ b/components/freemodbus/port/port.h
@@ -37,7 +37,7 @@
 #define MB_SERIAL_BUF_SIZE          (CONFIG_FMB_SERIAL_BUF_SIZE)
 
 // common definitions for serial port implementations
-#define MB_SERIAL_TX_TOUT_MS        (100)
+#define MB_SERIAL_TX_TOUT_MS        (2200) // maximum time for transmission of longest allowed frame buffer
 #define MB_SERIAL_TX_TOUT_TICKS     pdMS_TO_TICKS(MB_SERIAL_TX_TOUT_MS) // timeout for transmission
 #define MB_SERIAL_RX_TOUT_MS        (1)
 #define MB_SERIAL_RX_TOUT_TICKS     pdMS_TO_TICKS(MB_SERIAL_RX_TOUT_MS) // timeout for receive
diff --git a/components/freemodbus/port/portserial_m.c b/components/freemodbus/port/portserial_m.c
index feddbf75af..1ab6ae7f3c 100644
--- a/components/freemodbus/port/portserial_m.c
+++ b/components/freemodbus/port/portserial_m.c
@@ -114,7 +114,7 @@ BOOL xMBMasterPortSerialTxPoll(void)
         ESP_LOGD(TAG, "MB_TX_buffer sent: (%d) bytes.", (uint16_t)(usCount - 1));
         // Waits while UART sending the packet
         esp_err_t xTxStatus = uart_wait_tx_done(ucUartNumber, MB_SERIAL_TX_TOUT_TICKS);
-        vMBMasterPortSerialEnable( TRUE, FALSE );
+        vMBMasterPortSerialEnable(TRUE, FALSE);
         MB_PORT_CHECK((xTxStatus == ESP_OK), FALSE, "mb serial sent buffer failure.");
         return TRUE;
     }