diff --git a/src/calibre/devices/kindle/driver.py b/src/calibre/devices/kindle/driver.py
index f7e88f4ba5..4c4c21c5d3 100644
--- a/src/calibre/devices/kindle/driver.py
+++ b/src/calibre/devices/kindle/driver.py
@@ -15,7 +15,7 @@ from calibre.constants import DEBUG
 from calibre.devices.kindle.bookmark import Bookmark
 from calibre.devices.usbms.driver import USBMS
 from calibre import strftime, fsync, prints
-from polyglot.builtins import unicode_type
+from polyglot.builtins import unicode_type, as_bytes
 
 '''
 Notes on collections:
@@ -433,7 +433,7 @@ class KINDLE2(KINDLE):
         if path_map:
             for book in bl:
                 path = '/mnt/us/'+book.lpath
-                h = hashlib.sha1(path).hexdigest()
+                h = hashlib.sha1(as_bytes(path)).hexdigest()
                 if h in path_map:
                     book.device_collections = list(sorted(path_map[h]))
 
diff --git a/src/calibre/devices/smart_device_app/driver.py b/src/calibre/devices/smart_device_app/driver.py
index 532aac5d8b..177787d5b8 100644
--- a/src/calibre/devices/smart_device_app/driver.py
+++ b/src/calibre/devices/smart_device_app/driver.py
@@ -1027,7 +1027,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
             password = self.settings().extra_customization[self.OPT_PASSWORD]
             if password:
                 challenge = isoformat(now())
-                hasher = hashlib.new('sha1')
+                hasher = hashlib.sha1()
                 hasher.update(password.encode('UTF-8'))
                 hasher.update(challenge.encode('UTF-8'))
                 hash_digest = hasher.hexdigest()