diff --git a/src/calibre/debug.py b/src/calibre/debug.py
index 6ad49dfe65..63e11ae368 100644
--- a/src/calibre/debug.py
+++ b/src/calibre/debug.py
@@ -62,7 +62,7 @@ def migrate(old, new):
 
 def debug_device_driver():
     from calibre.devices import debug
-    print debug()
+    debug(ioreg_to_tmp=True, buf=sys.stdout)
     if iswindows:
         raw_input('Press Enter to continue...')
 
diff --git a/src/calibre/devices/__init__.py b/src/calibre/devices/__init__.py
index 95e33cbd24..3fead7b75f 100644
--- a/src/calibre/devices/__init__.py
+++ b/src/calibre/devices/__init__.py
@@ -27,14 +27,15 @@ def strftime(epoch, zone=time.gmtime):
     src[2] = INVERSE_MONTH_MAP[int(src[2])]
     return ' '.join(src)
 
-def debug():
+def debug(ioreg_to_tmp=False, buf=None):
     from calibre.customize.ui import device_plugins
     from calibre.devices.scanner import DeviceScanner
     from calibre.constants import iswindows, isosx, __version__
     from calibre import prints
     oldo, olde = sys.stdout, sys.stderr
 
-    buf = StringIO()
+    if buf is None:
+        buf = StringIO()
     sys.stdout = sys.stderr = buf
     try:
         out = partial(prints, file=buf)
@@ -82,16 +83,17 @@ def debug():
         connected_devices = []
         for dev in device_plugins():
             out('Looking for', dev.__class__.__name__)
-            connected = s.is_device_connected(dev, debug=True)
+            connected, det = s.is_device_connected(dev, debug=True)
             if connected:
-                connected_devices.append(dev)
+                connected_devices.append((dev, det))
 
         errors = {}
         success = False
-        for dev in connected_devices:
+        for dev, det in connected_devices:
             out('Device possibly connected:', dev.__class__.name)
             out('Trying to open device...', end=' ')
             try:
+                dev.reset(detected_device=det)
                 dev.open()
                 out('OK')
             except:
@@ -112,11 +114,17 @@ def debug():
                 out(' ')
 
         if ioreg is not None:
+            ioreg = 'IOREG Output\n'+ioreg
             out(' ')
-            out('IOREG Output')
-            out(ioreg)
+            if ioreg_to_tmp:
+                open('/tmp/ioreg.txt', 'wb').write(ioreg)
+                out('Dont forget to send the contents of /tmp/ioreg.txt')
+                out('You can open it with the command: open /tmp/ioreg.txt')
+            else:
+                out(ioreg)
 
-        return buf.getvalue().decode('utf-8')
+        if hasattr(buf, 'getvalue'):
+            return buf.getvalue().decode('utf-8')
     finally:
         sys.stdout = oldo
         sys.stderr = olde
diff --git a/src/calibre/devices/usbms/device.py b/src/calibre/devices/usbms/device.py
index b1f748835c..e239699a4e 100644
--- a/src/calibre/devices/usbms/device.py
+++ b/src/calibre/devices/usbms/device.py
@@ -460,9 +460,9 @@ class Device(DeviceConfig, DevicePlugin):
 
         matches.sort(cmp=dcmp)
         drives = {'main':matches[0]}
-        if len(matches > 1):
+        if len(matches) > 1:
             drives['carda'] = matches[1]
-        if len(matches > 2):
+        if len(matches) > 2:
             drives['cardb'] = matches[2]
 
         return drives
@@ -476,11 +476,13 @@ class Device(DeviceConfig, DevicePlugin):
 
     def open_osx(self):
         drives = self.osx_bsd_names()
+        bsd_drives = dict(**drives)
         drives = self.osx_sort_names(drives)
         mount_map = usbobserver.get_mounted_filesystems()
         for k, v in drives.items():
-            drives[k] = mount_map.get(k, None)
+            drives[k] = mount_map.get(v, None)
         if drives['main'] is None:
+            print bsd_drives, mount_map, drives
             raise DeviceError(_('Unable to detect the %s mount point. Try rebooting.')%self.__class__.__name__)
         self._main_prefix = drives['main']+os.sep
         def get_card_prefix(c):