diff --git a/src/calibre/devices/prs505/books.py b/src/calibre/devices/prs505/books.py
index 855d8d5cd3..7f4071a6cf 100644
--- a/src/calibre/devices/prs505/books.py
+++ b/src/calibre/devices/prs505/books.py
@@ -291,7 +291,6 @@ class BookList(_BookList):
                     db_id = book.application_id
                     if db_id is None:
                         db_id = book.db_id
-                        print 'here', db_id
                     if db_id is not None:
                         imap[book.application_id] = sony_id
             # filter the list, removing books not on device but on playlist
diff --git a/src/calibre/devices/prs505/driver.py b/src/calibre/devices/prs505/driver.py
index 1d403cb75d..9ff88da592 100644
--- a/src/calibre/devices/prs505/driver.py
+++ b/src/calibre/devices/prs505/driver.py
@@ -13,8 +13,7 @@ import os
 import re
 
 from calibre.devices.usbms.driver import USBMS
-from calibre.devices.usbms.books import Book
-from calibre.devices.prs505.books import BookList, fix_ids
+from calibre.devices.prs505.books import BookList as PRS_BookList, fix_ids
 from calibre.devices.prs505 import MEDIA_XML
 from calibre.devices.prs505 import CACHE_XML
 from calibre import __appname__
@@ -28,6 +27,8 @@ class PRS505(USBMS):
     supported_platforms = ['windows', 'osx', 'linux']
     path_sep = '/'
 
+    booklist_class = PRS_BookList # See USBMS for some explanation of this
+
     FORMATS      = ['epub', 'lrf', 'lrx', 'rtf', 'pdf', 'txt']
 
     VENDOR_ID    = [0x054c]   #: SONY Vendor Id
@@ -59,11 +60,6 @@ class PRS505(USBMS):
 
     METADATA_CACHE = "database/cache/metadata.calibre"
 
-    def initialize(self):
-        USBMS.initialize(self) # Must be first, so _class vars are set right
-        self.booklist_class = BookList
-        self.book_class = Book
-
     def windows_filter_pnp_id(self, pnp_id):
         return '_LAUNCHER' in pnp_id
 
diff --git a/src/calibre/devices/usbms/driver.py b/src/calibre/devices/usbms/driver.py
index 1fdf3bdf84..64b27a993d 100644
--- a/src/calibre/devices/usbms/driver.py
+++ b/src/calibre/devices/usbms/driver.py
@@ -27,6 +27,10 @@ class USBMS(CLI, Device):
     author         = _('John Schember')
     supported_platforms = ['windows', 'osx', 'linux']
 
+    # Store type instances of BookList and Book. We must do this because
+    # a) we need to override these classes in some device drivers, and
+    # b) the classmethods seem only to see real attributes declared in the
+    #    class, not attributes stored in the class
     booklist_class = BookList
     book_class = Book
 
@@ -34,11 +38,6 @@ class USBMS(CLI, Device):
     CAN_SET_METADATA = True
     METADATA_CACHE = 'metadata.calibre'
 
-    def initialize(self):
-        Device.initialize(self)
-#        self.booklist_class = BookList
-#        self.book_class = Book
-
     def get_device_information(self, end_session=True):
         self.report_progress(1.0, _('Get device information...'))
         return (self.get_gui_name(), '', '', '')