diff --git a/Lib/email/base64mime.py b/Lib/email/base64mime.py
index 0035b79..369bf10 100644
--- a/Lib/email/base64mime.py
+++ b/Lib/email/base64mime.py
@@ -101,25 +101,19 @@
 
 
 
-def decode(s, convert_eols=False):
+def decode(string):
     """Decode a raw base64 string, returning a bytes object.
 
-    If convert_eols is set to a string value, all canonical email linefeeds,
-    e.g. "\\r\\n", in the decoded text will be converted to the value of
-    convert_eols.  os.linesep is a good choice for convert_eols if you are
-    decoding a text attachment.
-
     This function does not parse a full MIME header value encoded with
     base64 (like =?iso-8895-1?b?bmloISBuaWgh?=) -- please use the high
     level email.Header class for that functionality.
     """
-    if not s:
-        return s
-
-    dec = a2b_base64(s)
-    if convert_eols:
-        return dec.replace(CRLF, convert_eols)
-    return dec
+    if not string:
+        return bytes()
+    elif isinstance(string, str):
+        return a2b_base64(string.encode('raw-unicode-escape'))
+    else:
+        return a2b_base64(s)
 
 
 # For convenience and backwards compatibility w/ standard base64 module
diff --git a/Lib/email/header.py b/Lib/email/header.py
index e03e42d..786a71f 100644
--- a/Lib/email/header.py
+++ b/Lib/email/header.py
@@ -341,10 +341,11 @@
         self._current_line = _Accumulator(headerlen)
 
     def __str__(self):
-        # Remove the trailing TRANSITIONAL_SPACE
-        last_line = self._current_line.pop()
-        if last_line is not TRANSITIONAL_SPACE:
-            self._current_line.push(last_line)
+        # Remove any trailing TRANSITIONAL_SPACE
+        if len(self._current_line) > 0:
+            last_line = self._current_line.pop()
+            if last_line is not TRANSITIONAL_SPACE:
+                self._current_line.push(last_line)
         self.newline()
         return NL.join(self._lines)
 
diff --git a/Lib/email/message.py b/Lib/email/message.py
index 50d6604..e368737 100644
--- a/Lib/email/message.py
+++ b/Lib/email/message.py
@@ -201,7 +201,8 @@
                 # Incorrect padding
                 pass
         elif cte in ('x-uuencode', 'uuencode', 'uue', 'x-uue'):
-            in_file = BytesIO(bytes(payload + '\n'))
+            payload += '\n'
+            in_file = BytesIO(payload.encode('raw-unicode-escape'))
             out_file = BytesIO()
             try:
                 uu.decode(in_file, out_file, quiet=True)
@@ -752,7 +753,8 @@
                 # LookupError will be raised if the charset isn't known to
                 # Python.  UnicodeError will be raised if the encoded text
                 # contains a character not in the charset.
-                charset = str(bytes(charset[2]), pcharset)
+                as_bytes = charset[2].encode('raw-unicode-escape')
+                charset = str(as_bytes, pcharset)
             except (LookupError, UnicodeError):
                 charset = charset[2]
         # charset characters must be in us-ascii range
diff --git a/Lib/email/quoprimime.py b/Lib/email/quoprimime.py
index 1301e0b..e59479c 100644
--- a/Lib/email/quoprimime.py
+++ b/Lib/email/quoprimime.py
@@ -58,7 +58,7 @@
 _QUOPRI_BODY_MAP = _QUOPRI_HEADER_MAP.copy()
 
 # Safe header bytes which need no encoding.
-for c in b'-!*+/' + bytes(ascii_letters, 'ascii') + bytes(digits, 'ascii'):
+for c in b'-!*+/' + ascii_letters.encode('ascii') + digits.encode('ascii'):
     _QUOPRI_HEADER_MAP[c] = chr(c)
 # Headers have one other special encoding; spaces become underscores.
 _QUOPRI_HEADER_MAP[ord(' ')] = '_'
diff --git a/Lib/email/test/test_email.py b/Lib/email/test/test_email.py
index 78d702d..f7cac97 100644
--- a/Lib/email/test/test_email.py
+++ b/Lib/email/test/test_email.py
@@ -2538,10 +2538,8 @@
 
     def test_decode(self):
         eq = self.assertEqual
-        eq(base64mime.decode(''), '')
+        eq(base64mime.decode(''), b'')
         eq(base64mime.decode('aGVsbG8='), b'hello')
-        eq(base64mime.decode('aGVsbG8=', 'X'), b'hello')
-        eq(base64mime.decode('aGVsbG8NCndvcmxk\n', 'X'), b'helloXworld')
 
     def test_encode(self):
         eq = self.assertEqual