diff --git a/test/bytecode_3.3/10_while1_popblock.pyc b/test/bytecode_3.3/10_while1_popblock.pyc
new file mode 100644
index 00000000..1dd6eb6d
Binary files /dev/null and b/test/bytecode_3.3/10_while1_popblock.pyc differ
diff --git a/test/bytecode_3.4/10_while1_popblock.pyc b/test/bytecode_3.4/10_while1_popblock.pyc
new file mode 100644
index 00000000..e8eb908d
Binary files /dev/null and b/test/bytecode_3.4/10_while1_popblock.pyc differ
diff --git a/test/simple_source/bug33/10_while1_popblock.py b/test/simple_source/bug33/10_while1_popblock.py
new file mode 100644
index 00000000..3219141b
--- /dev/null
+++ b/test/simple_source/bug33/10_while1_popblock.py
@@ -0,0 +1,17 @@
+# From 3.4.4 mailcap.py
+# Bug was needing a grammar rule to add POP_BLOCK before the end of the while1.
+# 3.3 apparently doesn't add this.
+def readmailcapfile(line):
+    while 1:
+        if not line: break
+        if line[0] == '#' or line.strip() == '':
+            continue
+        if not line:
+            continue
+        for j in range(3):
+            line[j] = line[j].strip()
+        if '/' in line:
+            line['/'].append('a')
+        else:
+            line['/'] = 'a'
+    return
diff --git a/uncompyle6/parsers/parse34.py b/uncompyle6/parsers/parse34.py
index e1259a9a..6ec70252 100644
--- a/uncompyle6/parsers/parse34.py
+++ b/uncompyle6/parsers/parse34.py
@@ -1,4 +1,17 @@
-#  Copyright (c) 2017 Rocky Bernstein
+#  Copyright (c) 2017-2018 Rocky Bernstein
+
+#  This program is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation, either version 3 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 spark grammar differences over Python 3.3 for Python 3.4
 """
@@ -18,6 +31,9 @@ class Python34Parser(Python33Parser):
         expr ::= LOAD_ASSERT
 
 
+        while1stmt    ::= SETUP_LOOP l_stmts
+                          COME_FROM JUMP_BACK POP_BLOCK COME_FROM_LOOP
+
         # FIXME the below masks a bug in not detecting COME_FROM_LOOP
         # grammar rules with COME_FROM -> COME_FROM_LOOP already exist
         whileelsestmt     ::= SETUP_LOOP testexpr l_stmts_opt JUMP_BACK POP_BLOCK
@@ -30,8 +46,9 @@ class Python34Parser(Python33Parser):
         """
 
     def customize_grammar_rules(self, tokens, customize):
-        # self.remove_rules("""
-        # """)
+        self.remove_rules("""
+        while1stmt ::= SETUP_LOOP l_stmts COME_FROM JUMP_BACK COME_FROM_LOOP
+        """)
         super(Python34Parser, self).customize_grammar_rules(tokens, customize)
         return