Update a README file.

configs/nucleo-f072rb/README.txt

@@ -8,12 +8,42 @@ Nucleo-F072RB README
 Contents
 ========
 
+  - Status
   - Nucleo-64 Boards
   - LEDs
   - Buttons
   - Serial Console
   - Configurations
 
+Status
+======
+  2017-04-27:  There are many problems.  On start up, I have to reset
+    several times before I get NSH prompt (or parts of it).  Apparently the
+    STM32 is either hanging (perhaps in clockconfig()) or perhaps it has
+    taken a hard fault before it is able to generate debug output?
+
+   There are many hardfaults during initial serial output.  This change
+   seems to eliminate those hardfaults:
+
+      @@ -2163,7 +2163,7 @@ static void stm32f0serial_txint(FAR struct uart_dev_s *dev, bool enable)
+            * interrupts disabled (note this may recurse).
+            */
+
+    -      uart_xmitchars(dev);
+    +//      uart_xmitchars(dev);
+     #endif
+         }
+       else
+
+   Which implies that the hardfaults are due to runaway recursion in the
+   serial driver?  This suggest some error in either determining when there
+   is TX data available or in disabling TX interrupts.
+
+   But this not a solution.  Even without the hard faults, it may hang
+   attempting to output the NSH greeting and prompt or hang unable to
+   receive input.  These symptoms suggest some issue with TX and RX
+   interrupt handling.
+
 Nucleo-64 Boards
 ================