diff --git a/trusty/utils/coverage-controller/controller.cpp b/trusty/utils/coverage-controller/controller.cpp
index 381a45285..f5d70b16d 100644
--- a/trusty/utils/coverage-controller/controller.cpp
+++ b/trusty/utils/coverage-controller/controller.cpp
@@ -60,6 +60,7 @@ void Controller::run(std::string output_dir) {
                 filename.insert(0, output_dir);
                 android::base::Result<void> res = record_list_[index]->SaveFile(filename);
                 counters[index]++;
+                WRITE_ONCE(control->read_buffer_cnt, counters[index]);
             }
             if(complete_cnt == counters[index] &&
                 !(flags & FLAG_RUN)) {
diff --git a/trusty/utils/coverage-controller/controller.h b/trusty/utils/coverage-controller/controller.h
index f7789bfed..841a1aeb1 100644
--- a/trusty/utils/coverage-controller/controller.h
+++ b/trusty/utils/coverage-controller/controller.h
@@ -35,9 +35,9 @@
 struct control {
     /* Written by controller, read by instrumented TA */
     uint64_t        cntrl_flags;
+    uint64_t        read_buffer_cnt;
 
     /* Written by instrumented TA, read by controller */
-    uint64_t        oper_flags;
     uint64_t        write_buffer_start_count;
     uint64_t        write_buffer_complete_count;
 };