diff --git a/subsys/net/lib/openthread/platform/platform-zephyr.h b/subsys/net/lib/openthread/platform/platform-zephyr.h
index f09a2d15f0788a..e1a5ca6d3cabc7 100644
--- a/subsys/net/lib/openthread/platform/platform-zephyr.h
+++ b/subsys/net/lib/openthread/platform/platform-zephyr.h
@@ -54,6 +54,12 @@ void platformRadioProcess(otInstance *aInstance);
  */
 void platformUartProcess(otInstance *aInstance);
 
+/**
+ * Outer component calls this method to notify UART driver that it should
+ * switch to panic mode and work in synchronous way.
+ */
+void platformUartPanic(void);
+
 /**
  * Get current channel from radio driver.
  *
diff --git a/subsys/net/lib/openthread/platform/uart.c b/subsys/net/lib/openthread/platform/uart.c
index 86ca768409ba5e..c46be97d87df5f 100644
--- a/subsys/net/lib/openthread/platform/uart.c
+++ b/subsys/net/lib/openthread/platform/uart.c
@@ -29,7 +29,6 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 #include "platform-zephyr.h"
 
 struct openthread_uart {
-	struct ring_buf *tx_ringbuf;
 	struct ring_buf *rx_ringbuf;
 	struct device *dev;
 	atomic_t tx_busy;
@@ -37,10 +36,8 @@ struct openthread_uart {
 };
 
 #define OT_UART_DEFINE(_name, _ringbuf_size) \
-	RING_BUF_DECLARE(_name##_tx_ringbuf, _ringbuf_size); \
 	RING_BUF_DECLARE(_name##_rx_ringbuf, _ringbuf_size); \
 	static struct openthread_uart _name = { \
-		.tx_ringbuf = &_name##_tx_ringbuf, \
 		.rx_ringbuf = &_name##_rx_ringbuf, \
 	}
 
@@ -48,6 +45,10 @@ OT_UART_DEFINE(ot_uart, CONFIG_OPENTHREAD_NCP_UART_RING_BUFFER_SIZE);
 
 #define RX_FIFO_SIZE 128
 
+static bool is_panic_mode;
+static const uint8_t *s_write_buffer = NULL;
+static uint16_t       s_write_length = 0;
+
 static void uart_rx_handle(void)
 {
 	u8_t *data;
@@ -90,17 +91,11 @@ static void uart_rx_handle(void)
 static void uart_tx_handle(void)
 {
 	u32_t len;
-	const u8_t *data;
-
-	len = ring_buf_get_claim(ot_uart.tx_ringbuf, (u8_t **)&data,
-				 ot_uart.tx_ringbuf->size);
-	if (len) {
-		int err;
 
-		len = uart_fifo_fill(ot_uart.dev, data, len);
-		err = ring_buf_get_finish(ot_uart.tx_ringbuf, len);
-		(void)err;
-		__ASSERT_NO_MSG(err == 0);
+	if (s_write_length) {
+		len = uart_fifo_fill(ot_uart.dev, s_write_buffer, s_write_length);
+		s_write_buffer += len;
+		s_write_length -= len;
 	} else {
 		uart_irq_tx_disable(ot_uart.dev);
 		ot_uart.tx_busy = 0;
@@ -197,23 +192,66 @@ otError otPlatUartEnable(void)
 
 otError otPlatUartDisable(void)
 {
-	/* TODO: uninit UART */
-	LOG_WRN("%s not implemented.", __func__);
-	return OT_ERROR_NOT_IMPLEMENTED;
+#ifdef CONFIG_OPENTHREAD_NCP_SPINEL_ON_UART_ACM
+	int ret = usb_disable();
+
+	if (ret) {
+		LOG_WRN("Failed to disable USB, ret code %d", ret);
+	}
+#endif
+
+	uart_irq_tx_disable(ot_uart.dev);
+	uart_irq_rx_disable(ot_uart.dev);
+	return OT_ERROR_NONE;
 };
 
 
 otError otPlatUartSend(const u8_t *aBuf, u16_t aBufLength)
 {
-	size_t cnt = ring_buf_put(ot_uart.tx_ringbuf, aBuf, aBufLength);
+	if (NULL == aBuf) {
+		return OT_ERROR_FAILED;
+	}
+
+	s_write_buffer = aBuf;
+	s_write_length = aBufLength;
 
 	if (atomic_set(&(ot_uart.tx_busy), 1) == 0) {
-		uart_irq_tx_enable(ot_uart.dev);
+		if (is_panic_mode) {
+			/* In panic mode all data have to be send immediately
+			 * without using interrupts
+		 	 */
+			otPlatUartFlush();
+		} else {
+			uart_irq_tx_enable(ot_uart.dev);
+		}
 	}
 
-	if (cnt == aBufLength) {
-		return OT_ERROR_NONE;
-	} else {
-		return OT_ERROR_BUSY;
-	}
+	return OT_ERROR_NONE;
 };
+
+otError otPlatUartFlush(void)
+{
+	u32_t len;
+	otError result = OT_ERROR_NONE;
+
+	if (s_write_length) {
+		for (size_t i = 0; i < len; i++) {
+		     uart_poll_out(ot_uart.dev, s_write_buffer+i);
+		}
+	}
+
+	ot_uart.tx_busy = 0;
+	atomic_set(&(ot_uart.tx_finished), 1);
+	otSysEventSignalPending();
+	return result;
+}
+
+void platformUartPanic(void)
+{
+	is_panic_mode = true;
+	/* In panic mode data are send without using interrupts.
+	 * Reception in this mode is not supported.
+	 */
+	uart_irq_tx_disable(ot_uart.dev);
+	uart_irq_rx_disable(ot_uart.dev);
+}