diff --git a/lib/blocklib.php b/lib/blocklib.php
index 296c55d4bba..b2101c3ed6b 100644
--- a/lib/blocklib.php
+++ b/lib/blocklib.php
@@ -710,6 +710,8 @@ class block_manager {
         $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = bi.id AND ctx.contextlevel = :contextlevel)";
 
         $systemcontext = context_system::instance();
+        list($bpcontext, $bpcontextidparams) = $DB->get_in_or_equal(array($context->id, $systemcontext->id),
+                SQL_PARAMS_NAMED, 'bpcontextid');
         $params = array(
             'contextlevel' => CONTEXT_BLOCK,
             'subpage1' => $this->page->subpage,
@@ -743,7 +745,7 @@ class block_manager {
                 FROM {block_instances} bi
                 JOIN {block} b ON bi.blockname = b.name
                 LEFT JOIN {block_positions} bp ON bp.blockinstanceid = bi.id
-                                                  AND bp.contextid = :contextid1
+                                                  AND bp.contextid $bpcontext
                                                   AND bp.pagetype = :pagetype
                                                   AND bp.subpage = :subpage1
                 $ccjoin
@@ -761,7 +763,8 @@ class block_manager {
                     COALESCE(bp.weight, bi.defaultweight),
                     bi.id";
 
-        $allparams = $params + $parentcontextparams + $pagetypepatternparams + $requiredbythemeparams + $requiredbythemenotparams;
+        $allparams = $params + $parentcontextparams + $pagetypepatternparams + $requiredbythemeparams;
+        $allparams = $allparams + $requiredbythemenotparams + $bpcontextidparams;
         $blockinstances = $DB->get_recordset_sql($sql, $allparams);
 
         $this->birecordsbyregion = $this->prepare_per_region_arrays();