diff --git a/bbb_cape/src/bbb/bbb.gyp b/bbb_cape/src/bbb/bbb.gyp
index 1da4732..5f5b590 100644
--- a/bbb_cape/src/bbb/bbb.gyp
+++ b/bbb_cape/src/bbb/bbb.gyp
@@ -46,6 +46,17 @@
       ],
     },
     {
+      'target_name': 'export_uart',
+      'type': 'static_library',
+      'sources': [
+        'export_uart.cc',
+      ],
+      'dependencies': [
+        '<(AOS)/build/aos.gyp:logging',
+        '<(AOS)/common/common.gyp:time',
+      ],
+    },
+    {
       'target_name': 'uart_reader',
       'type': 'static_library',
       'sources': [
@@ -56,6 +67,7 @@
         '<(AOS)/build/aos.gyp:logging',
         '<(AOS)/common/common.gyp:time',
         'byte_io',
+        'export_uart',
       ],
       'export_dependent_settings': [
         '<(AOS)/common/common.gyp:time',
diff --git a/bbb_cape/src/bbb/export_uart.cc b/bbb_cape/src/bbb/export_uart.cc
new file mode 100644
index 0000000..ccf751c
--- /dev/null
+++ b/bbb_cape/src/bbb/export_uart.cc
@@ -0,0 +1,59 @@
+#include "bbb/export_uart.h"
+
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include "aos/common/logging/logging.h"
+#include "aos/common/time.h"
+
+namespace bbb {
+namespace {
+
+// TODO(brians): Determine this in some way that allows easy switching for
+// testing with /dev/ttyUSB0 for example.
+const char *device = "/dev/ttyO1";
+
+bool easy_access(const char *path) {
+  if (access(path, R_OK | W_OK) == 0) return true;
+  if (errno == EACCES || errno == ENOENT) return false;
+  LOG(FATAL, "access(%s, F_OK) failed with %d: %s\n", path, errno,
+      strerror(errno));
+}
+
+}  // namespace
+
+const char *UartDevice() { return device; }
+
+void ExportUart() {
+  if (easy_access(device)) {
+    LOG(INFO, "unexporting BB-UART1\n");
+    if (system("bash -c 'echo -$(cat /sys/devices/bone_capemgr.*/slots"
+               " | fgrep BB-UART1"
+               " | cut -d : -f 1 | tr -d \" \")"
+               " > /sys/devices/bone_capemgr.*/slots'") == -1) {
+      LOG(FATAL, "system([disable OMAP UART]) failed with %d: %s\n", errno,
+          strerror(errno));
+    }
+    while (easy_access(device)) {
+      LOG(DEBUG, "waiting for BB-UART1 to be unexported\n");
+      ::aos::time::SleepFor(::aos::time::Time::InSeconds(0.1));
+    }
+  }
+
+  LOG(INFO, "exporting BB-UART1\n");
+  // 2 strings to work around a VIM bug where the indenter locks up when they're
+  // combined as 1...
+  if (system("bash -c 'echo BB-UART1 > /sys/devices/bone_capemgr.*"
+             "/slots'") ==
+      -1) {
+    LOG(FATAL, "system([enable OMAP UART]) failed with %d: %s\n", errno,
+        strerror(errno));
+  }
+  while (!easy_access(device)) {
+    LOG(DEBUG, "waiting for BB-UART1 to be exported\n");
+    ::aos::time::SleepFor(::aos::time::Time::InSeconds(0.1));
+  }
+}
+
+}  // namespace bbb
diff --git a/bbb_cape/src/bbb/export_uart.h b/bbb_cape/src/bbb/export_uart.h
new file mode 100644
index 0000000..4f91a57
--- /dev/null
+++ b/bbb_cape/src/bbb/export_uart.h
@@ -0,0 +1,15 @@
+#ifndef BBB_EXPORT_UART_H_
+#define BBB_EXPORT_UART_H_
+
+namespace bbb {
+
+// Returns a pointer to static memory with the name of the device file for the
+// UART.
+const char *UartDevice();
+
+// Unexports (if already exported) and then reexports the UART cape slot.
+void ExportUart();
+
+}  // namespace bbb
+
+#endif  // BBB_EXPORT_UART_H_
diff --git a/bbb_cape/src/bbb/uart_reader.cc b/bbb_cape/src/bbb/uart_reader.cc
index 9abb284..7f88d51 100644
--- a/bbb_cape/src/bbb/uart_reader.cc
+++ b/bbb_cape/src/bbb/uart_reader.cc
@@ -7,6 +7,8 @@
 
 #include "aos/common/logging/logging.h"
 
+#include "bbb/export_uart.h"
+
 // This is the code for receiving data from the cape via UART.
 // fragment active.
 // `su -c "echo BB-UART1 > /sys/devices/bone_capemgr.*/slots"` works, but
@@ -16,48 +18,10 @@
 namespace bbb {
 namespace {
 
-// TODO(brians): Determine this in some way that allows easy switching for
-// testing with /dev/ttyUSB0 for example.
-const char *device = "/dev/ttyO1";
-
-bool easy_access(const char *path) {
-  if (access(path, R_OK | W_OK) == 0) return true;
-  if (errno == EACCES || errno == ENOENT) return false;
-  LOG(FATAL, "access(%s, F_OK) failed with %d: %s\n", path, errno,
-      strerror(errno));
-}
-
 int open_device() {
-  if (easy_access(device)) {
-    LOG(INFO, "unexporting BB-UART1\n");
-    if (system("bash -c 'echo -$(cat /sys/devices/bone_capemgr.*/slots"
-               " | fgrep BB-UART1"
-               " | cut -d : -f 1 | tr -d \" \")"
-               " > /sys/devices/bone_capemgr.*/slots'") == -1) {
-      LOG(FATAL, "system([disable OMAP UART]) failed with %d: %s\n", errno,
-          strerror(errno));
-    }
-    while (easy_access(device)) {
-      LOG(DEBUG, "waiting for BB-UART1 to be unexported\n");
-      ::aos::time::SleepFor(::aos::time::Time::InSeconds(0.1));
-    }
-  }
+  ExportUart();
 
-  LOG(INFO, "exporting BB-UART1\n");
-  // 2 strings to work around a VIM bug where the indenter locks up when they're
-  // combined as 1...
-  if (system("bash -c 'echo BB-UART1 > /sys/devices/bone_capemgr.*"
-             "/slots'") ==
-      -1) {
-    LOG(FATAL, "system([enable OMAP UART]) failed with %d: %s\n", errno,
-        strerror(errno));
-  }
-  while (!easy_access(device)) {
-    LOG(DEBUG, "waiting for BB-UART1 to be exported\n");
-    ::aos::time::SleepFor(::aos::time::Time::InSeconds(0.1));
-  }
-
-  return open(device, O_RDWR | O_NOCTTY | O_NONBLOCK);
+  return open(UartDevice(), O_RDWR | O_NOCTTY | O_NONBLOCK);
 }
 
 }  // namespace
@@ -77,7 +41,7 @@
   
   if (fd_ < 0) {
     LOG(FATAL, "open(%s, O_RDWR | O_NOCTTY | O_NOBLOCK) failed with %d: %s\n",
-        device, errno, strerror(errno));
+        UartDevice(), errno, strerror(errno));
   }
 
   if (aos_uart_reader_set_tty_options(fd_, baud_rate) != 0) {
diff --git a/bbb_cape/src/flasher/flasher.gyp b/bbb_cape/src/flasher/flasher.gyp
index 2d506b8..fba1477 100644
--- a/bbb_cape/src/flasher/flasher.gyp
+++ b/bbb_cape/src/flasher/flasher.gyp
@@ -17,6 +17,7 @@
         '<(EXTERNALS):stm32flash',
         '<(AOS)/build/aos.gyp:logging',
         '<(DEPTH)/bbb_cape/src/bbb/bbb.gyp:gpios',
+        '<(DEPTH)/bbb_cape/src/bbb/bbb.gyp:export_uart',
         '<(AOS)/common/common.gyp:time',
       ],
     },
diff --git a/bbb_cape/src/flasher/stm32_flasher.cc b/bbb_cape/src/flasher/stm32_flasher.cc
index 48887d2..a48abc4 100644
--- a/bbb_cape/src/flasher/stm32_flasher.cc
+++ b/bbb_cape/src/flasher/stm32_flasher.cc
@@ -19,6 +19,7 @@
 }
 
 #include "bbb/gpo.h"
+#include "bbb/export_uart.h"
 
 namespace {
 
@@ -48,9 +49,6 @@
   }
   ::std::string target = argv[1];
 
-  //::std::string device = "/dev/ttyUSB0";
-  // TODO(brians): Figure out an intelligent way to set the device to use.
-  ::std::string device = "/dev/ttyO1";
   serial_baud_t baud_rate = SERIAL_BAUD_57600;
 
   ::std::string filename =
@@ -112,17 +110,21 @@
     LOG(FATAL, "opening file %s failed\n", filename.c_str());
   }
 
-  serial_t *serial = serial_open(device.c_str());
+  ::bbb::ExportUart();
+
+  const char *device = ::bbb::UartDevice();
+
+  serial_t *serial = serial_open(device);
   if (serial == NULL) {
     LOG(FATAL, "failed to open serial port %s because of %d: %s\n",
-        device.c_str(), errno, strerror(errno));
+        device, errno, strerror(errno));
   }
   if (serial_setup(serial, baud_rate,
                    SERIAL_BITS_8,
                    SERIAL_PARITY_EVEN,
                    SERIAL_STOPBIT_1) != SERIAL_ERR_OK) {
     LOG(FATAL, "setting up serial port %s failed because of %d: %s\n",
-        device.c_str(), errno, strerror(errno));
+        device, errno, strerror(errno));
   }
   LOG(INFO, "serial configuration: %s\n", serial_get_setup_str(serial));