diff --git a/arch/c5471/src/up_blocktask.c b/arch/c5471/src/up_blocktask.c
index 6b42d42702..5e0693e2e3 100644
--- a/arch/c5471/src/up_blocktask.c
+++ b/arch/c5471/src/up_blocktask.c
@@ -95,8 +95,6 @@ void up_block_task(_TCB *tcb, tstate_t task_state)
       _TCB *rtcb = (_TCB*)g_readytorun.head;
       boolean switch_needed;
 
-      dbg("Blocking TCB=%p\n", tcb);
-
       /* Remove the tcb task from the ready-to-run list.  If we
        * are blocking the task at the head of the task list (the
        * most likely case), then a context switch to the next
diff --git a/arch/c5471/src/up_doirq.c b/arch/c5471/src/up_doirq.c
index f4e07873cd..ab1b40d655 100644
--- a/arch/c5471/src/up_doirq.c
+++ b/arch/c5471/src/up_doirq.c
@@ -74,6 +74,13 @@ void up_doirq(int irq, uint32* regs)
 #else
   if ((unsigned)irq < NR_IRQS)
     {
+       /* Current regs non-zero indicates that we are processing
+        * an interrupt; current_regs is also used to manage
+        * interrupt level context switches.
+        */
+
+       current_regs = regs;
+
        /* Mask and acknowledge the interrupt */
 
        up_maskack_irq(irq);
@@ -82,8 +89,15 @@ void up_doirq(int irq, uint32* regs)
 
        irq_dispatch(irq, regs);
 
-       /* Then unmask it */
+       /* Indicate that we are no long in an interrupt handler */
 
+       current_regs = NULL;
+
+       /* Unmask the last interrupt (global interrupts are still
+        * disabled.
+        */
+
+       current_regs = NULL;
        up_enable_irq(irq);
     }
   up_ledoff(LED_INIRQ);
diff --git a/arch/c5471/src/up_serial.c b/arch/c5471/src/up_serial.c
index c6d6dc58ef..022befd380 100644
--- a/arch/c5471/src/up_serial.c
+++ b/arch/c5471/src/up_serial.c
@@ -521,7 +521,7 @@ static inline void up_givesem(sem_t *sem)
  * characters from the tail of the buffer.
  */
 
-static inline void up_recvchars(up_dev_t *dev)
+static void up_recvchars(up_dev_t *dev)
 {
   uint16 status;
   int nexthead = dev->recv.head + 1;
@@ -800,6 +800,32 @@ static void shutdown(up_dev_t * dev)
   irqrestore(flags);
 }
 
+/************************************************************
+ * Name: up_irqwrite
+ ************************************************************/
+
+static ssize_t up_irqwrite(up_dev_t *dev, const char *buffer, size_t buflen)
+{
+  ssize_t ret = buflen;
+
+  /* Force each character through the low level interface */
+
+  for (; buflen; buflen--)
+    {
+      int ch = *buffer++;
+      up_lowputc(ch);
+
+     /* If this is the console, then we should replace LF with LF-CR */
+
+      if (ch == '\n')
+        {
+          up_lowputc('\r');
+        }
+    }
+
+  return ret;
+}
+
 /************************************************************
  * Name: up_write
  ************************************************************/
@@ -810,6 +836,23 @@ static ssize_t up_write(struct file *filep, const char *buffer, size_t buflen)
   up_dev_t     *dev      = inode->i_private;
   ssize_t       ret      = buflen;
 
+  /* We may receive console writes through this path from
+   * interrupt handlers!  In this case, we will need to do
+   * things a little differently.
+   */
+
+  if (up_interrupt_context())
+    {
+      if (dev->isconsole)
+        {
+          return up_irqwrite(dev, buffer, buflen);
+        }
+      else
+        {
+          return ERROR;
+        }
+    }
+
   /* Only one user can be accessing dev->xmit.head at once */
 
   up_takesem(&dev->xmit.sem);
@@ -827,10 +870,10 @@ static ssize_t up_write(struct file *filep, const char *buffer, size_t buflen)
       /* Put the character into the transmit buffer */
 
       up_putxmitchar(dev, ch);
- 
+
      /* If this is the console, then we should replace LF with LF-CR */
 
-      if (ch == '\n')
+      if (dev->isconsole && ch == '\n')
         {
           up_putxmitchar(dev, '\r');
         }
@@ -895,7 +938,7 @@ static ssize_t up_read(struct file *filep, char *buffer, size_t buflen)
     }
 
   up_enablerxint(dev);
-  up_takesem(&dev->recv.sem);
+  up_givesem(&dev->recv.sem);
   return ret;
 }