diff --git a/base/device.py b/base/device.py

index 6d7add9..bf27307 100644

--- a/base/device.py

+++ b/base/device.py

@@ -2264,7 +2264,8 @@ class Device(object):

                 self.callback()

         if total_bytes_to_write != bytes_out:

-            raise Error(ERROR_DEVICE_IO_ERROR)

+            raise Error(ERROR_DEVICE_IO_ERROR, 'Number of written '

+                        'bytes by hpmudext mismatch with expected amount.')

         return bytes_out

diff --git a/base/g.py b/base/g.py

index 9856662..0aa0e2e 100644

--- a/base/g.py

+++ b/base/g.py

@@ -398,9 +398,11 @@ ERROR_STRINGS = {

 class Error(Exception):

-    def __init__(self, opt=ERROR_INTERNAL):

+    def __init__(self, opt=ERROR_INTERNAL, msg=None):

         self.opt = opt

         self.msg = ERROR_STRINGS.get(opt, ERROR_STRINGS[ERROR_INTERNAL])

+        if msg:

+            self.msg = '{} - {}'.format(self.msg, msg)

         log.debug("Exception: %d (%s)" % (opt, self.msg))

         Exception.__init__(self, self.msg, opt)

diff --git a/prnt/ldl.py b/prnt/ldl.py

index e3f77f7..8b28e7f 100644

--- a/prnt/ldl.py

+++ b/prnt/ldl.py

@@ -145,7 +145,7 @@ def buildLIDILPacket(packet_type, command=0, operation=0, other={}):

         p = '$\x00\x10\x00\x08\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff$'

     elif packet_type == PACKET_TYPE_RESET_LIDIL:

-        p = '$\x00\x10\x00\x06\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff$'

+        p = b'$\x00\x10\x00\x06\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff$'

     elif packet_type == PACKET_TYPE_COMMAND: