diff --git a/Kconfig.utestcases b/Kconfig.utestcases
index e402aff6508..69a8a43885a 100644
--- a/Kconfig.utestcases
+++ b/Kconfig.utestcases
@@ -4,6 +4,7 @@ menu "RT-Thread Utestcases"
         bool "RT-Thread Utestcases"
         default n
         select RT_USING_UTEST
+        select RT_USING_DEBUG if !RT_USING_ULOG
 
     if RT_USING_UTESTCASES
 
diff --git a/components/drivers/serial/utest/Kconfig b/components/drivers/serial/utest/Kconfig
index aefb162b8b5..18c75b2574c 100644
--- a/components/drivers/serial/utest/Kconfig
+++ b/components/drivers/serial/utest/Kconfig
@@ -16,6 +16,10 @@ menu "Serial Test"
             string "Device Name for Serial Test"
             default "uart2"
 
+        config RT_SERIAL_TC_DEVICE_USING_TX_DMA
+            bool "Selected serial device is using TX DMA"
+            default n
+
         config RT_SERIAL_TC_RXBUF_SIZE
             int "RX Buffer Size for Serial Test"
             default 128
diff --git a/components/drivers/serial/utest/v2/uart_flush_txb.c b/components/drivers/serial/utest/v2/uart_flush_txb.c
index 3e99e77ecac..060976ce01d 100644
--- a/components/drivers/serial/utest/v2/uart_flush_txb.c
+++ b/components/drivers/serial/utest/v2/uart_flush_txb.c
@@ -64,7 +64,8 @@ static rt_err_t test_item(rt_uint8_t *uart_write_buffer, rt_uint32_t send_size)
     rt_device_control(&serial->parent, RT_SERIAL_CTRL_TX_FLUSH, RT_NULL);
     tick_diff = rt_tick_get() - old_tick;
 
-    if (tick_diff < expect_time || tick_diff > (expect_time + 10))
+    rt_uint32_t lower_bound = (expect_time > 2) ? (expect_time - 2) : 0;
+    if (tick_diff < lower_bound || tick_diff > (expect_time + 10))
     {
         LOG_E("send_size [%4d], time required for TXB mode transmission to complete [%3d], expect_time [%3d]", send_size, tick_diff, expect_time);
         return -RT_ERROR;
diff --git a/components/drivers/serial/utest/v2/uart_flush_txnb.c b/components/drivers/serial/utest/v2/uart_flush_txnb.c
index e300df286c8..b8c722e71f7 100644
--- a/components/drivers/serial/utest/v2/uart_flush_txnb.c
+++ b/components/drivers/serial/utest/v2/uart_flush_txnb.c
@@ -64,7 +64,8 @@ static rt_err_t test_item(rt_uint8_t *uart_write_buffer, rt_uint32_t send_size)
     rt_device_control(&serial->parent, RT_SERIAL_CTRL_TX_FLUSH, RT_NULL);
     tick_diff = rt_tick_get() - old_tick;
 
-    if (tick_diff < expect_time || tick_diff > (expect_time + 10))
+    rt_uint32_t lower_bound = (expect_time > 2) ? (expect_time - 2) : 0;
+    if (tick_diff < lower_bound || tick_diff > (expect_time + 10))
     {
         LOG_E("send_size [%4d], time required for TXNB mode transmission to complete [%3d], expect_time [%3d]", send_size, tick_diff, expect_time);
         return -RT_ERROR;
diff --git a/components/drivers/serial/utest/v2/uart_timeout_txb.c b/components/drivers/serial/utest/v2/uart_timeout_txb.c
index d60e9bd02ca..e070725dfa9 100644
--- a/components/drivers/serial/utest/v2/uart_timeout_txb.c
+++ b/components/drivers/serial/utest/v2/uart_timeout_txb.c
@@ -14,7 +14,7 @@
 #include <stdlib.h>
 
 #ifdef RT_UTEST_SERIAL_V2
-#ifndef BSP_UART2_TX_USING_DMA
+#ifndef RT_SERIAL_TC_DEVICE_USING_TX_DMA
 
 static struct rt_serial_device *serial;