diff --git a/prebuilt/common/bin/otasigcheck.sh b/prebuilt/common/bin/otasigcheck.sh
index 5131be3..7bf1228 100644
--- a/prebuilt/common/bin/otasigcheck.sh
+++ b/prebuilt/common/bin/otasigcheck.sh
@@ -12,12 +12,13 @@
 if [ -f /data/system/packages.xml -a -f /tmp/releasekey ]; then
   relCert=$(grep -A3 'package name="com.android.htmlviewer"' /data/system/packages.xml  | grep "cert index" | head -n 1 | sed -e 's|.*"\([[:digit:]][[:digit:]]*\)".*|\1|g')
 
+  # Tools missing? Err on the side of caution and exit cleanly
+  if [ "z$relCert" == "z" ]; then exit 0; fi
+
   grep "cert index=\"$relCert\"" /data/system/packages.xml | grep -q `cat /tmp/releasekey`
   if [ $? -ne 0 ]; then
      echo "You have an installed system that isn't signed with this build's key, aborting..."
-     # Edify doesn't abort on non-zero executions, so let's trash the key and use sha1sum instead
-     echo "INVALID" > /tmp/releasekey
-     exit 1
+     exit 124
   fi
 fi