diff --git a/arch/arm/src/kinetis/kinetis_lowputc.c b/arch/arm/src/kinetis/kinetis_lowputc.c
index 5529443c37e..a808e091759 100644
--- a/arch/arm/src/kinetis/kinetis_lowputc.c
+++ b/arch/arm/src/kinetis/kinetis_lowputc.c
@@ -424,10 +424,18 @@ void kinetis_uartconfigure(uintptr_t uart_base, uint32_t baud,
 
   putreg8(UART_PFIFO_RXFE | UART_PFIFO_TXFE, uart_base+KINETIS_UART_PFIFO_OFFSET);
 #else
+  /* Otherwise, disable the FIFOs.  Then the FIFOs are disable, the effective
+   * FIFO depth is 1.  So set the watermarks as follows:
+   *
+   * TWFIFO[TXWATER] = 0:  TDRE will be set when the number of queues bytes
+   *  (1 in this case) is less than or equal to 0.
+   * RWFIFO[RXWATER] = 1:  RDRF will be set when the number of queues bytes
+   *  (1 in this case) is greater than or equal to 1.
+   * 
   /* Set the watermarks to one and disable the FIFOs */
 
   putreg8(1, uart_base+KINETIS_UART_RWFIFO_OFFSET);
-  putreg8(1, uart_base+KINETIS_UART_TWFIFO_OFFSET);
+  putreg8(0, uart_base+KINETIS_UART_TWFIFO_OFFSET);
   putreg8(0, uart_base+KINETIS_UART_PFIFO_OFFSET);
 #endif