diff -Nru ubuntu-release-upgrader-0.220.6/debian/changelog ubuntu-release-upgrader-0.220.6mg1/debian/changelog
--- ubuntu-release-upgrader-0.220.6/debian/changelog	2014-11-14 00:10:47.000000000 +0200
+++ ubuntu-release-upgrader-0.220.6mg1/debian/changelog	2015-02-04 09:03:30.000000000 +0200
@@ -1,3 +1,10 @@
+ubuntu-release-upgrader (1:0.220.6mg1) trusty; urgency=medium
+
+  * DistUpgrade/DistUpgradeViewText.py:
+    - flush stdout before reading user input. (LP: #1417880)
+
+ -- Marius Gedminas <marius@gedmin.as>  Wed, 04 Feb 2015 09:02:32 +0200
+
 ubuntu-release-upgrader (1:0.220.6) trusty-proposed; urgency=medium
 
   * data/removal_blacklist.cfg: make update-manager blacklist entry more
diff -Nru ubuntu-release-upgrader-0.220.6/DistUpgrade/DistUpgradeViewText.py ubuntu-release-upgrader-0.220.6mg1/DistUpgrade/DistUpgradeViewText.py
--- ubuntu-release-upgrader-0.220.6/DistUpgrade/DistUpgradeViewText.py	2014-11-14 00:08:13.000000000 +0200
+++ ubuntu-release-upgrader-0.220.6mg1/DistUpgrade/DistUpgradeViewText.py	2015-02-04 09:02:28.000000000 +0200
@@ -44,6 +44,7 @@
 
 def readline():
     """ py2/py3 compatible readline from stdin """
+    sys.stdout.flush()
     s = sys.stdin.readline()
     if hasattr(s, "decode"):
         return s.decode(ENCODING, "backslashreplace")