diff --git a/hddtemp b/hddtemp
index 2a2f00b..798a36f 100755
--- a/hddtemp
+++ b/hddtemp
@@ -1,16 +1,31 @@
 #!/usr/bin/perl
 
+# A replacement for the various stock versions of hddtemp that all
+# seem to have big issues with different types of drives, or spin up
+# drives that are in powersaving spun-down mode, etc.
+
+# For those disks like some of my SAS drives where `smartctl
+# --nocheck=standby` and `hdparm -C` actually spins up the disk,
+# detect whether a disk is spun down with sdparm commands, and don't
+# invoke smartctl if it is.  Otherwise, some of our other disks like
+# our 16TB SATA drives on Dell Perc controllers give unreliable status to `sdparm
+# --command=sense`, but `smartctl --nocheck=standby` does seem to
+# reliably detect their spundown state anyway, so we continue to
+# supply `--nocheck=standby` to cover this case.
+
+# Much of this stolen from /etc/munin/plugins/hddtemp_smartctl
+
 use strict;
 use warnings;
 
-# much of this stolen from /etc/munin/plugins/hddtemp_smartctl
-
 $ENV{PATH}="$ENV{PATH}:/usr/sbin:/sbin";
 
+my $last_exit=0;
 foreach my $drive (@ARGV) {
   my $sense=`sdparm --command=sense $drive 2>/dev/null`;
   if (!($sense =~ /Standby/)) {
-    my $output=`smartctl -A -i --nocheck=standby $drive`;
+    my $output=`smartctl -A -i --nocheck=standby,0 $drive`;
+    $last_exit = $?>>8;
 
     my $model="";
     if ($output =~ /(Model Number|Device Model):\s*(.*)/) {
@@ -36,3 +51,5 @@ foreach my $drive (@ARGV) {
     print "$drive: Sleeping.  Temperature not available\n";
   };
 }
+
+exit $last_exit;