--- pt-table-checksum	2012-02-03 19:06:52.000000000 -0500
+++ pt-table-checksum.new	2012-02-03 19:06:41.000000000 -0500
@@ -6376,12 +6376,12 @@
             sth  => $sth->{explain_upper_boundary},
             vals => [ @{$boundary->{lower}}, $nibble_iter->chunk_size() ],
          );
-         if ( ($expl->{key} || '') ne $nibble_iter->nibble_index() ) {
+         if ( (lc($expl->{key}) || '') ne lc($nibble_iter->nibble_index()) ) {
             PTDEBUG && _d('Cannot nibble next chunk, aborting table');
             if ( $o->get('quiet') < 2 ) {
                warn ts("Aborting $tbl->{db}.$tbl->{tbl} because "
                   . ($nibble_iter->nibble_number() + 1)
-                  . " cannot be nibbled safely.\n");
+                  . " cannot be nibbled safely. " . ($expl->{key}) . " ne " . ($nibble_iter->nibble_index()) . "\n");
             }
             $tbl->{checksum_results}->{errors}++;
             return 0; # stop nibbling table
@@ -6437,7 +6437,7 @@
                :          0;
 
             # Ensure that MySQL is using the chunk index.
-            if ( ($expl->{key} || '') ne $nibble_iter->nibble_index() ) {
+            if ( lc($expl->{key} || '') ne lc($nibble_iter->nibble_index()) ) {
                PTDEBUG && _d('Chunk', $args{nibbleno}, 'of table',
                   "$tbl->{db}.$tbl->{tbl} not using chunk index, skipping");
                return 0;  # next boundary