diff --git a/arch/arm/src/arm/up_assert.c b/arch/arm/src/arm/up_assert.c
index 27788451daf..f081035a316 100644
--- a/arch/arm/src/arm/up_assert.c
+++ b/arch/arm/src/arm/up_assert.c
@@ -151,7 +151,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/arm/src/armv6-m/up_assert.c b/arch/arm/src/armv6-m/up_assert.c
index 93ff4a9f6fb..934f8b255b3 100644
--- a/arch/arm/src/armv6-m/up_assert.c
+++ b/arch/arm/src/armv6-m/up_assert.c
@@ -193,7 +193,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/arm/src/armv7-a/arm_assert.c b/arch/arm/src/armv7-a/arm_assert.c
index bdeffa763cf..1fef0e7eb07 100644
--- a/arch/arm/src/armv7-a/arm_assert.c
+++ b/arch/arm/src/armv7-a/arm_assert.c
@@ -185,7 +185,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/arm/src/armv7-m/up_assert.c b/arch/arm/src/armv7-m/up_assert.c
index eedfa522d81..144ea69fa76 100644
--- a/arch/arm/src/armv7-m/up_assert.c
+++ b/arch/arm/src/armv7-m/up_assert.c
@@ -198,7 +198,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/arm/src/armv7-r/arm_assert.c b/arch/arm/src/armv7-r/arm_assert.c
index ccf01160457..4e3137512ae 100644
--- a/arch/arm/src/armv7-r/arm_assert.c
+++ b/arch/arm/src/armv7-r/arm_assert.c
@@ -186,7 +186,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/avr/src/common/up_assert.c b/arch/avr/src/common/up_assert.c
index a93187c5238..7457fb8821a 100644
--- a/arch/avr/src/common/up_assert.c
+++ b/arch/avr/src/common/up_assert.c
@@ -109,7 +109,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/hc/src/m9s12/m9s12_assert.c b/arch/hc/src/m9s12/m9s12_assert.c
index 2f859314f1d..b4a96f199c4 100644
--- a/arch/hc/src/m9s12/m9s12_assert.c
+++ b/arch/hc/src/m9s12/m9s12_assert.c
@@ -144,7 +144,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/mips/src/mips32/up_assert.c b/arch/mips/src/mips32/up_assert.c
index 119844eb997..e8873b45671 100644
--- a/arch/mips/src/mips32/up_assert.c
+++ b/arch/mips/src/mips32/up_assert.c
@@ -109,7 +109,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/sh/src/common/up_assert.c b/arch/sh/src/common/up_assert.c
index 95abc9b1903..0c3e9a6b858 100644
--- a/arch/sh/src/common/up_assert.c
+++ b/arch/sh/src/common/up_assert.c
@@ -110,7 +110,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/x86/src/common/up_assert.c b/arch/x86/src/common/up_assert.c
index 3b6caececce..a011c101b82 100644
--- a/arch/x86/src/common/up_assert.c
+++ b/arch/x86/src/common/up_assert.c
@@ -103,7 +103,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/z16/src/common/up_assert.c b/arch/z16/src/common/up_assert.c
index 628c34f1faa..9a755d63aa7 100644
--- a/arch/z16/src/common/up_assert.c
+++ b/arch/z16/src/common/up_assert.c
@@ -109,7 +109,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/arch/z80/src/common/up_assert.c b/arch/z80/src/common/up_assert.c
index 49b72409289..1bbfa09a24a 100644
--- a/arch/z80/src/common/up_assert.c
+++ b/arch/z80/src/common/up_assert.c
@@ -108,7 +108,7 @@ static int usbtrace_syslog(FAR const char *fmt, ...)
   /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_EMERG, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/drivers/syslog/syslog.h b/drivers/syslog/syslog.h
index ac52ebb0e14..7a90bb3541a 100644
--- a/drivers/syslog/syslog.h
+++ b/drivers/syslog/syslog.h
@@ -224,6 +224,25 @@ int syslog_flush_intbuffer(FAR const struct syslog_channel_s *channel,
 
 int syslog_putc(int ch);
 
+/****************************************************************************
+ * Name: syslog_force
+ *
+ * Description:
+ *   This is the low-level system logging interface.  This version forces
+ *   the output and is only used in emergency situations (e.g., in assertion
+ *   handling).
+ *
+ * Input Parameters:
+ *   ch - The character to add to the SYSLOG (must be positive).
+ *
+ * Returned Value:
+ *   On success, the character is echoed back to the caller.  A negated
+ *   errno value is returned on any failure.
+ *
+ ****************************************************************************/
+
+int syslog_force(int ch);
+
 /****************************************************************************
  * Name: syslog_dev_putc
  *
diff --git a/drivers/syslog/syslog_channel.c b/drivers/syslog/syslog_channel.c
index 4f1cc44339b..fbdde1fdf91 100644
--- a/drivers/syslog/syslog_channel.c
+++ b/drivers/syslog/syslog_channel.c
@@ -210,6 +210,40 @@ int syslog_putc(int ch)
     }
 }
 
+/****************************************************************************
+ * Name: syslog_force
+ *
+ * Description:
+ *   This is the low-level system logging interface.  This version forces
+ *   the output and is only used in emergency situations (e.g., in assertion
+ *   handling).
+ *
+ * Input Parameters:
+ *   ch - The character to add to the SYSLOG (must be positive).
+ *
+ * Returned Value:
+ *   On success, the character is echoed back to the caller.  A negated
+ *   errno value is returned on any failure.
+ *
+ ****************************************************************************/
+
+int syslog_force(int ch)
+{
+  DEBUGASSERT(g_syslog_channel != NULL && g_syslog_channel->sc_force != NULL);
+
+#ifdef CONFIG_SYSLOG_INTBUFFER
+  /* Flush any characters that may have been added to the interrupt
+   * buffer through the emergency channel
+   */
+
+  (void)syslog_flush_intbuffer(g_syslog_channel, true);
+#endif
+
+  /* Then send the character to the emergency channel */
+
+  return g_syslog_channel->sc_force(ch);
+}
+
 /****************************************************************************
  * Name: syslog_flush
  *
diff --git a/drivers/syslog/syslog_stream.c b/drivers/syslog/syslog_stream.c
index 491da95c266..ecb68d256bf 100644
--- a/drivers/syslog/syslog_stream.c
+++ b/drivers/syslog/syslog_stream.c
@@ -86,6 +86,39 @@ static void syslogstream_putc(FAR struct lib_outstream_s *this, int ch)
   while (errno == -EINTR);
 }
 
+/****************************************************************************
+ * Name: emergstream_putc
+ ****************************************************************************/
+
+static void emergstream_putc(FAR struct lib_outstream_s *this, int ch)
+{
+  int ret;
+
+  /* Try writing until the write was successful or until an irrecoverable
+   * error occurs.
+   */
+
+  do
+    {
+      /* Write the character to the supported logging device.  On failure,
+       * syslog_putc returns EOF with the errno value set;
+       */
+
+      ret = syslog_force(ch);
+      if (ret != EOF)
+        {
+          this->nput++;
+          return;
+        }
+
+      /* The special errno value -EINTR means that syslog_putc() was
+       * awakened by a signal.  This is not a real error and must be
+       * ignored in this context.
+       */
+    }
+  while (errno == -EINTR);
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -114,3 +147,28 @@ void syslogstream(FAR struct lib_outstream_s *stream)
 #endif
   stream->nput  = 0;
 }
+
+/****************************************************************************
+ * Name: emergstream
+ *
+ * Description:
+ *   Initializes a stream for use with the configured emergency syslog
+ *   interface.  Only accessible from with the OS SYSLOG logic.
+ *
+ * Input parameters:
+ *   stream - User allocated, uninitialized instance of struct
+ *            lib_lowoutstream_s to be initialized.
+ *
+ * Returned Value:
+ *   None (User allocated instance initialized).
+ *
+ ****************************************************************************/
+
+void emergstream(FAR struct lib_outstream_s *stream)
+{
+  stream->put   = emergstream_putc;
+#ifdef CONFIG_STDIO_LINEBUFFER
+  stream->flush = lib_noflush;
+#endif
+  stream->nput  = 0;
+}
diff --git a/drivers/syslog/vsyslog.c b/drivers/syslog/vsyslog.c
index ee87a1019e1..27fab399ecb 100644
--- a/drivers/syslog/vsyslog.c
+++ b/drivers/syslog/vsyslog.c
@@ -57,16 +57,15 @@
  *
  * Description:
  *   _vsyslog() handles the system logging system calls. It is functionally
- *   equivalent to vsyslog() except that the per-process priority filtering
- *   has already been performed and, hence, there is no priority argument.
- *
- *   NOTE:  The va_list parameter is passed by reference.  That is because
- *   the va_list is a structure in some compilers and passing of structures
- *   in the NuttX sycalls does not work.
+ *   equivalent to vsyslog() except that (1) the per-process priority
+ *   filtering has already been performed and the va_list parameter is
+ *   passed by reference.  That is because the va_list is a structure in
+ *   some compilers and passing of structures in the NuttX sycalls does
+ *   not work.
  *
  ****************************************************************************/
 
-int _vsyslog(FAR const IPTR char *fmt, FAR va_list *ap)
+int _vsyslog(int priority, FAR const IPTR char *fmt, FAR va_list *ap)
 {
   struct lib_outstream_s stream;
 #ifdef CONFIG_SYSLOG_TIMESTAMP
@@ -87,17 +86,28 @@ int _vsyslog(FAR const IPTR char *fmt, FAR va_list *ap)
 #endif
 
   /* Wrap the low-level output in a stream object and let lib_vsprintf
-   * do the work.
+   * do the work.  NOTE that emergency priority output is handled
+   * differently.. it will use the SYSLOG emergency stream.
    */
 
-  syslogstream((FAR struct lib_outstream_s *)&stream);
+  if (priority == LOG_EMERG)
+    {
+      /* Use the SYSLOG emergency stream */
+
+      emergstream((FAR struct lib_outstream_s *)&stream);
+    }
+  else
+    {
+      /* Use the normal SYSLOG stream */
+
+      syslogstream((FAR struct lib_outstream_s *)&stream);
+    }
 
 #if defined(CONFIG_SYSLOG_TIMESTAMP)
   /* Pre-pend the message with the current time, if available */
 
   (void)lib_sprintf((FAR struct lib_outstream_s *)&stream,
                     "[%6d.%06d]", ts.tv_sec, ts.tv_nsec/1000);
-
 #endif
 
   return lib_vsprintf((FAR struct lib_outstream_s *)&stream, fmt, *ap);
diff --git a/drivers/usbdev/usbdev_trace.c b/drivers/usbdev/usbdev_trace.c
index b532565e0e0..857cd3e0294 100644
--- a/drivers/usbdev/usbdev_trace.c
+++ b/drivers/usbdev/usbdev_trace.c
@@ -100,10 +100,10 @@ static int usbtrace_syslog(const char *fmt, ...)
   va_list ap;
   int ret;
 
-  /* Let lowvsyslog do the real work */
+  /* Let vsyslog do the real work */
 
   va_start(ap, fmt);
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
+  ret = vsyslog(LOG_INFO, fmt, ap);
   va_end(ap);
   return ret;
 }
diff --git a/include/nuttx/streams.h b/include/nuttx/streams.h
index cf52324f2f7..6ae6b8c9430 100644
--- a/include/nuttx/streams.h
+++ b/include/nuttx/streams.h
@@ -371,6 +371,24 @@ void lib_nulloutstream(FAR struct lib_outstream_s *nulloutstream);
 
 void syslogstream(FAR struct lib_outstream_s *stream);
 
+/****************************************************************************
+ * Name: emergstream
+ *
+ * Description:
+ *   Initializes a stream for use with the configured emergency syslog
+ *   interface.  Only accessible from with the OS SYSLOG logic.
+ *
+ * Input parameters:
+ *   stream - User allocated, uninitialized instance of struct
+ *            lib_lowoutstream_s to be initialized.
+ *
+ * Returned Value:
+ *   None (User allocated instance initialized).
+ *
+ ****************************************************************************/
+
+void emergstream(FAR struct lib_outstream_s *stream);
+
 /****************************************************************************
  * Name: lib_noflush
  *
diff --git a/include/nuttx/syslog/syslog.h b/include/nuttx/syslog/syslog.h
index b0d6694b596..c897a34801c 100644
--- a/include/nuttx/syslog/syslog.h
+++ b/include/nuttx/syslog/syslog.h
@@ -219,16 +219,15 @@ int syslog_flush(void);
  *
  * Description:
  *   _vsyslog() handles the system logging system calls. It is functionally
- *   equivalent to vsyslog() except that the per-process priority filtering
- *   has already been performed and, hence, there is no priority argument.
- *
- *   NOTE:  The va_list parameter is passed by reference.  That is because
- *   the va_list is a structure in some compilers and passing of structures
- *   in the NuttX sycalls does not work.
+ *   equivalent to vsyslog() except that (1) the per-process priority
+ *   filtering has already been performed and the va_list parameter is
+ *   passed by reference.  That is because the va_list is a structure in
+ *   some compilers and passing of structures in the NuttX sycalls does
+ *   not work.
  *
  ****************************************************************************/
 
-int _vsyslog(FAR const IPTR char *src, FAR va_list *ap);
+int _vsyslog(int priority, FAR const IPTR char *src, FAR va_list *ap);
 
 #undef EXTERN
 #ifdef __cplusplus
diff --git a/libc/misc/lib_debug.c b/libc/misc/lib_debug.c
index 5fefcd2c433..d921c7c32ab 100644
--- a/libc/misc/lib_debug.c
+++ b/libc/misc/lib_debug.c
@@ -66,7 +66,7 @@ int _alert(const char *format, ...)
   int     ret;
 
   va_start(ap, format);
-  ret = lowvsyslog(LOG_EMERG, format, ap);
+  ret = vsyslog(LOG_EMERG, format, ap);
   va_end(ap);
 
   return ret;
diff --git a/libc/stdio/lib_fprintf.c b/libc/stdio/lib_fprintf.c
index 191dc2e34a4..bb744c4698b 100644
--- a/libc/stdio/lib_fprintf.c
+++ b/libc/stdio/lib_fprintf.c
@@ -33,44 +33,12 @@
  *
  ****************************************************************************/
 
-/****************************************************************************
- * Compilation Switches
- ****************************************************************************/
-
 /****************************************************************************
  * Included Files
  ****************************************************************************/
 
 #include <stdio.h>
 
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
-/****************************************************************************
- * Private Type Declarations
- ****************************************************************************/
-
-/****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
-
-/****************************************************************************
- * Public Constant Data
- ****************************************************************************/
-
-/****************************************************************************
- * Public Data
- ****************************************************************************/
-
-/****************************************************************************
- * Private Constant Data
- ****************************************************************************/
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
diff --git a/libc/stdio/lib_printf.c b/libc/stdio/lib_printf.c
index 5f1096a3a2f..b760abb4bb9 100644
--- a/libc/stdio/lib_printf.c
+++ b/libc/stdio/lib_printf.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * libc/stdio/lib_printf.c
  *
- *   Copyright (C) 2007-2008, 2011-2012, 2014 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2008, 2011-2012, 2014, 2016 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -60,8 +60,6 @@ int printf(FAR const IPTR char *fmt, ...)
   ret = vfprintf(stdout, fmt, ap);
 #elif CONFIG_NFILE_DESCRIPTORS > 0
   ret = vsyslog(LOG_INFO, fmt, ap);
-#elif defined(CONFIG_ARCH_LOWPUTC)
-  ret = lowvsyslog(LOG_INFO, fmt, ap);
 #else
 # ifdef CONFIG_CPP_HAVE_WARNING
 #   warning "printf has no data sink"
diff --git a/libc/syslog/lib_syslog.c b/libc/syslog/lib_syslog.c
index ec9ca3b7e57..408ffc10015 100644
--- a/libc/syslog/lib_syslog.c
+++ b/libc/syslog/lib_syslog.c
@@ -67,14 +67,14 @@ int vsyslog(int priority, FAR const IPTR char *fmt, va_list ap)
 
   if ((g_syslog_mask & LOG_MASK(priority)) != 0)
     {
-      /* Yes.. lPerform the _vsyslog system call.
+      /* Yes.. Perform the _vsyslog system call.
        *
        * NOTE:  The va_list parameter is passed by reference.  That is
        * because the va_list is a structure in some compilers and passing
        * of structures in the NuttX sycalls does not work.
        */
 
-      ret = _vsyslog(fmt, &ap);
+      ret = _vsyslog(priority, fmt, &ap);
     }
 
   return ret;
diff --git a/syscall/syscall.csv b/syscall/syscall.csv
index 306d5c4cae9..29271925c46 100644
--- a/syscall/syscall.csv
+++ b/syscall/syscall.csv
@@ -159,7 +159,7 @@
 "up_assert","assert.h","","void","FAR const uint8_t*","int"
 #"up_assert","assert.h","","void"
 "vfork","unistd.h","defined(CONFIG_ARCH_HAVE_VFORK)","pid_t"
-"_vsyslog","syslog.h","","int","FAR const IPTR char*","FAR va_list*"
+"_vsyslog","syslog.h","","int","int","FAR const IPTR char*","FAR va_list*"
 "wait","sys/wait.h","defined(CONFIG_SCHED_WAITPID) && defined(CONFIG_SCHED_HAVE_PARENT)","pid_t","int*"
 "waitid","sys/wait.h","defined(CONFIG_SCHED_WAITPID) && defined(CONFIG_SCHED_HAVE_PARENT)","int","idtype_t","id_t"," FAR siginfo_t *","int"
 "waitpid","sys/wait.h","defined(CONFIG_SCHED_WAITPID)","pid_t","pid_t","int*","int"
diff --git a/syscall/syscall_lookup.h b/syscall/syscall_lookup.h
index 2194a6e6448..4cd1a3d6765 100644
--- a/syscall/syscall_lookup.h
+++ b/syscall/syscall_lookup.h
@@ -165,7 +165,7 @@ SYSCALL_LOOKUP(up_assert,                 2, STUB_up_assert)
 
 /* System logging */
 
-  SYSCALL_LOOKUP(_vsyslog,                2, STUB__vsyslog)
+  SYSCALL_LOOKUP(_vsyslog,                3, STUB__vsyslog)
 
 /* The following are defined if either file or socket descriptor are
  * enabled.
diff --git a/syscall/syscall_stublookup.c b/syscall/syscall_stublookup.c
index c587401b571..96862aa4062 100644
--- a/syscall/syscall_stublookup.c
+++ b/syscall/syscall_stublookup.c
@@ -167,7 +167,8 @@ uintptr_t STUB_timer_settime(int nbr, uintptr_t parm1, uintptr_t parm2,
 
 /* System logging */
 
-uintptr_t STUB__vsyslog(int nbr, uintptr_t parm1, uintptr_t parm2);
+uintptr_t STUB__vsyslog(int nbr, uintptr_t parm1, uintptr_t parm2,
+            uintptr_t parm3);
 
 /* The following are defined if either file or socket descriptor are
  * enabled.