diff --git a/ack-sync b/ack-sync
index e39c128..0e03a8e 100755
--- a/ack-sync
+++ b/ack-sync
@@ -251,7 +251,9 @@ def main(bug_numbers, all_package, all_version, all_section, update,
 			upload = True
 
 		# extract source
-		subprocess.check_call(["dpkg-source", "-x", dsc_file])
+		env = os.environ
+		env['DEB_VENDOR'] = 'Ubuntu'
+		subprocess.check_call(["dpkg-source", "-x", dsc_file], env=env)
 
 		build_source(dist, dsc_file)
 	
diff --git a/debian/changelog b/debian/changelog
index 2124d4d..92c53a6 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -7,8 +7,11 @@ ubuntu-dev-tools (0.107) UNRELEASED; urgency=low
     - Sort debian/install as well as debian/*.install
     - Add one-space-indentation option: --short-indent
     - Remove null-entry from trailing comma in sorted lists
+  * ack-sync, dgetlp, grab-merge, syncpackage: Export DEB_VENDOR=Ubuntu when
+    unpacking source packages. 3.0 (quilt) has optional per-vendor patch
+    series.
 
- -- Stefano Rivera <stefanor@ubuntu.com>  Wed, 24 Nov 2010 20:02:21 +0200
+ -- Stefano Rivera <stefanor@ubuntu.com>  Wed, 24 Nov 2010 21:04:46 +0200
 
 ubuntu-dev-tools (0.106) experimental; urgency=low
 
diff --git a/dgetlp b/dgetlp
index d6af8c3..39db656 100755
--- a/dgetlp
+++ b/dgetlp
@@ -221,9 +221,12 @@ def Download(dscinfo, number, filename, verify=True):
         error(107, "Error: %s", e)
 
 def unpack():
+    # Source format 3.0 can apply patches based on vendor
+    env = os.environ
+    env['DEB_VENDOR'] = 'Ubuntu'
     out = open('/dev/null', 'w')
     err = open('/dev/null', 'w')
-    ret = subprocess.call(unpack_cmd.split(), stdout=out, stderr=err)
+    ret = subprocess.Popen(unpack_cmd.split(), stdout=out, stderr=err, env=env)
     out.close()
     err.close()
     if ret:
diff --git a/grab-merge b/grab-merge
index 0befc63..f21becd 100755
--- a/grab-merge
+++ b/grab-merge
@@ -80,7 +80,7 @@ echo
 
 if grep "^generated: " REPORT >/dev/null; then
     VERSION=$(sed -n -e "/^generated:/s/^generated: *//p" REPORT)
-    dpkg-source -x ${MERGE}_${VERSION#*:}.dsc
+    DEB_VENDOR=Ubuntu dpkg-source -x ${MERGE}_${VERSION#*:}.dsc
     echo
 else
     TARBALL=$(sed -n -e "/\.src\.tar\.gz$/p" REPORT)
diff --git a/syncpackage b/syncpackage
index 164cca2..ebeaa16 100755
--- a/syncpackage
+++ b/syncpackage
@@ -275,11 +275,13 @@ def sync_dsc(script_name, dscurl, debian_dist, release, name, email, bugs,
 
     # extract package
     cmd = ['dpkg-source', '-x', dscname]
+    env = os.environ
+    env['DEB_VENDOR'] = 'Ubuntu'
     if not verbose:
         cmd.insert(1, "-q")
     if verbose:
         print_command(script_name, cmd)
-    subprocess.check_call(cmd)
+    subprocess.check_call(cmd, env=env)
 
     # Do a fake sync if required
     if len(fakesync_files) > 0: