diff --git a/src/calibre/devices/prs505/driver.py b/src/calibre/devices/prs505/driver.py
index 7facd4d3bb..e73a341909 100644
--- a/src/calibre/devices/prs505/driver.py
+++ b/src/calibre/devices/prs505/driver.py
@@ -69,13 +69,15 @@ class PRS505(CLI, Device):
 
         def write_cache(prefix):
             try:
-                cachep = os.path.join(prefix, self.CACHE_XML)
+                cachep = os.path.join(prefix, *(self.CACHE_XML.split('/')))
                 if not os.path.exists(cachep):
-                    try:
-                        os.makedirs(os.path.dirname(cachep), mode=0777)
-                    except:
-                        time.sleep(5)
-                        os.makedirs(os.path.dirname(cachep), mode=0777)
+                    dname = os.path.dirname(cachep)
+                    if not os.path.exists(dname):
+                        try:
+                            os.makedirs(dname, mode=0777)
+                        except:
+                            time.sleep(5)
+                            os.makedirs(dname, mode=0777)
                     with open(cachep, 'wb') as f:
                         f.write(u'''<?xml version="1.0" encoding="UTF-8"?>
                             <cache xmlns="http://www.kinoma.com/FskCache/1">