diff --git a/src/libprs500/__init__.py b/src/libprs500/__init__.py
index b61f4b68c0..f997919bbe 100644
--- a/src/libprs500/__init__.py
+++ b/src/libprs500/__init__.py
@@ -37,7 +37,7 @@ You may have to adjust the GROUP and the location of the rules file to
 suit your distribution.
 """
 
-__version__   = "0.3.5"
+__version__   = "0.3.6"
 __docformat__ = "epytext"
 __author__    = "Kovid Goyal <kovid@kovidgoyal.net>"
 
diff --git a/src/libprs500/communicate.py b/src/libprs500/communicate.py
index 7aae8ec18d..2653a454fe 100755
--- a/src/libprs500/communicate.py
+++ b/src/libprs500/communicate.py
@@ -260,7 +260,9 @@ class PRS500Device(Device):
         if version not in KNOWN_USB_PROTOCOL_VERSIONS:
             print >> sys.stderr, "WARNING: Usb protocol version " + \
                                 hex(version) + " is unknown"
-        res = self.send_validated_command(SetBulkSize(size=0x028000))
+        res = self.send_validated_command(SetBulkSize(\
+                          chunk_size = 512*self.bulk_read_max_packet_size, \
+                          unknown = 2))
         if res.code != 0: 
             raise ProtocolError("Unable to set bulk size.")
         self.send_validated_command(UnlockDevice(key=0x312d))
diff --git a/src/libprs500/gui/main.py b/src/libprs500/gui/main.py
index e12d86db6f..aeb334205a 100644
--- a/src/libprs500/gui/main.py
+++ b/src/libprs500/gui/main.py
@@ -177,6 +177,7 @@ class Main(QObject, Ui_MainWindow):
                 self.status("Syncing media list to card")
                 self.dev.upload_book_list(self.card_model.booklist)
             self.update_availabe_space()
+            self.model_modified()
         self.show_book(self.current_view.currentIndex(), QModelIndex())
         self.window.setCursor(Qt.ArrowCursor)
     
@@ -479,7 +480,8 @@ class Main(QObject, Ui_MainWindow):
         self.detector = DeviceConnectDetector(self.dev)
         self.connect(self.detector, SIGNAL("device_connected()"), \
                 self.establish_connection)
-        self.connect(self.detector, SIGNAL("device_removed()"), self.device_removed)
+        self.connect(self.detector, SIGNAL("device_removed()"), \
+                     self.device_removed)
         self.search.setFocus(Qt.OtherFocusReason)
         self.show_device(False)
         self.df_template = self.df.text()
diff --git a/src/libprs500/libusb.py b/src/libprs500/libusb.py
index 8e1be2329d..f6ce979580 100644
--- a/src/libprs500/libusb.py
+++ b/src/libprs500/libusb.py
@@ -253,6 +253,8 @@ class DeviceHandle(Structure):
         if rsize < 0:
                 raise Error('Could not read ' + str(size) + ' bytes on the '\
                             'bulk bus. Error code: ' + str(rsize))
+        if rsize == 0:
+                raise Error('Device sent zero bytes')
         if rsize < size:
             arr = arr[:rsize]
         return arr
diff --git a/src/libprs500/prstypes.py b/src/libprs500/prstypes.py
index 2f0dc55065..39cecc3fe8 100755
--- a/src/libprs500/prstypes.py
+++ b/src/libprs500/prstypes.py
@@ -46,6 +46,7 @@ import time
 
 from libprs500.errors import PacketError
 
+WORD      = "<H"    #: Unsigned integer little endian encoded in 2 bytes
 DWORD     = "<I"    #: Unsigned integer little endian encoded in 4 bytes
 DDWORD    = "<Q"    #: Unsigned long long little endian encoded in 8 bytes
 
@@ -402,12 +403,17 @@ class GetUSBProtocolVersion(ShortCommand):
         number=GetUSBProtocolVersion.NUMBER, \
         type=0x01, command=0x00)
 
-class SetBulkSize(ShortCommand):
+class SetBulkSize(Command):
     """ Set size for bulk transfers in this session """
     NUMBER = 0x107 #: Command number
-    def __init__(self, size=0x028000):
-        ShortCommand.__init__(self, \
-        number=SetBulkSize.NUMBER, type=0x01, command=size)
+    chunk_size = field(fmt=WORD, start=0x10)
+    unknown = field(fmt=WORD, start=0x12)
+    def __init__(self, chunk_size=0x8000, unknown=0x2):
+        Command.__init__(self, [0 for i in range(24)])
+        self.number = SetBulkSize.NUMBER
+        self.type = 0x01
+        self.chunk_size = chunk_size
+        self.unknown = unknown
 
 class UnlockDevice(ShortCommand):
     """ Unlock the device """
@@ -714,7 +720,8 @@ class Answer(TransferBuffer):
         if "__len__" in dir(packet):
             if len(packet) < 16 : 
                 raise PacketError(str(self.__class__)[7:-2] + \
-                " packets must have a length of atleast 16 bytes")
+                " packets must have a length of atleast 16 bytes. "\
+                "Got initializer of " + str(len(packet)) + " bytes.")
         elif packet < 16:
             raise PacketError(str(self.__class__)[7:-2] + \
             " packets must have a length of atleast 16 bytes")