diff --git a/src/calibre/devices/prs505/sony_cache.py b/src/calibre/devices/prs505/sony_cache.py
index fa4dd74b6d..727bdf68b2 100644
--- a/src/calibre/devices/prs505/sony_cache.py
+++ b/src/calibre/devices/prs505/sony_cache.py
@@ -12,7 +12,7 @@ from uuid import uuid4
 
 from lxml import etree
 
-from calibre import prints, guess_type, iswindows, islinux
+from calibre import prints, guess_type
 from calibre.devices.errors import DeviceError
 from calibre.devices.usbms.driver import debug_print
 from calibre.constants import DEBUG
@@ -47,10 +47,7 @@ def strptime(src):
     src[2] = str(MONTH_MAP[src[2]])
     return time.strptime(' '.join(src), '%w, %d %m %Y %H:%M:%S %Z')
 
-def strftime(epoch, zone=None):
-    zone = time.gmtime
-    if islinux:
-        zone = time.localtime
+def strftime(epoch, zone=time.localtime):
     src = time.strftime("%w, %d %m %Y %H:%M:%S GMT", zone(epoch)).split()
     src[0] = INVERSE_DAY_MAP[int(src[0][:-1])]+','
     src[2] = INVERSE_MONTH_MAP[int(src[2])]
@@ -427,9 +424,6 @@ class XMLCache(object):
 
     def update_text_record(self, record, book, path, bl_index):
         timestamp = os.path.getmtime(path)
-        # Correct for MS DST time 'adjustment'
-        if iswindows and time.daylight:
-            timestamp -= time.altzone - time.timezone
         date = strftime(timestamp)
         if date != record.get('date', None):
             record.set('date', date)