diff --git a/NEWS b/NEWS
index 7c7a177f4692c8f7de91b48dff3c043d41a79ffb..2c7673bc13af51125ac9e4c50ea8154d5bbd253b 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,13 @@
 News
 ====
 
+Version 2.1.2.1
+---------------
+
+*(Released Fri, 7 May 2010)*
+
+Fix a bug which prevented untagged KVM instances from starting.
+
 Version 2.1.2
 -------------
 
diff --git a/configure.ac b/configure.ac
index 521821f555a27c9ea44a989c5fa345ac14697249..a3c5d00b05d06b19e5312cde2b9252ba99ce58a3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@
 m4_define([gnt_version_major], [2])
 m4_define([gnt_version_minor], [1])
 m4_define([gnt_version_revision], [2])
-m4_define([gnt_version_suffix], [])
+m4_define([gnt_version_suffix], [.1])
 m4_define([gnt_version_full],
           m4_format([%d.%d.%d%s],
                     gnt_version_major, gnt_version_minor,
diff --git a/lib/hypervisor/hv_kvm.py b/lib/hypervisor/hv_kvm.py
index 76b4a1a60757d851a3fa8b1399a1d868e065fc2c..fdd117ab37399489603f7475a3134071d95254e8 100644
--- a/lib/hypervisor/hv_kvm.py
+++ b/lib/hypervisor/hv_kvm.py
@@ -287,7 +287,8 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     if nic.nicparams[constants.NIC_MODE] == constants.NIC_MODE_BRIDGED:
       script.write("export BRIDGE=%s\n" % nic.nicparams[constants.NIC_LINK])
     script.write("export INTERFACE=$1\n")
-    script.write("export TAGS=\"%s\"\n" % " ".join(instance.tags))
+    if instance.tags:
+      script.write("export TAGS=\"%s\"\n" % " ".join(instance.tags))
     # TODO: make this configurable at ./configure time
     script.write("if [ -x '%s' ]; then\n" % self._KVM_NETWORK_SCRIPT)
     script.write("  # Execute the user-specific vif file\n")