diff --git a/scripts/gnt-instance b/scripts/gnt-instance
index 43c4506eeb5249d207f9fec7755e56c6a3373a5c..720c90c8fcd0a2fe8968966f6f3307f462488612 100755
--- a/scripts/gnt-instance
+++ b/scripts/gnt-instance
@@ -539,7 +539,17 @@ def _FormatBlockDevInfo(buf, dev, indent_level):
       buf.write("not active\n")
     else:
       (path, major, minor, syncp, estt, degr, ldisk) = status
-      buf.write("%s (%d:%d)" % (path, major, minor))
+      if major is None:
+        major_string = "N/A"
+      else:
+        major_string = str(major)
+
+      if minor is None:
+        minor_string = "N/A"
+      else:
+        minor_string = str(minor)
+
+      buf.write("%s (%s:%s)" % (path, major_string, minor_string))
       if dtype in (constants.LD_MD_R1, constants.LD_DRBD7, constants.LD_DRBD8):
         if syncp is not None:
           sync_text = "*RECOVERING* %5.2f%%," % syncp