diff --git a/builder/sizes_test.go b/builder/sizes_test.go
index 8184040648..f4274708da 100644
--- a/builder/sizes_test.go
+++ b/builder/sizes_test.go
@@ -42,9 +42,9 @@ func TestBinarySize(t *testing.T) {
 	// This is a small number of very diverse targets that we want to test.
 	tests := []sizeTest{
 		// microcontrollers
-		{"hifive1b", "examples/echo", 4556, 280, 0, 2264},
-		{"microbit", "examples/serial", 2920, 388, 8, 2272},
-		{"wioterminal", "examples/pininterrupt", 7379, 1489, 116, 6912},
+		{"hifive1b", "examples/echo", 4580, 280, 0, 2264},
+		{"microbit", "examples/serial", 2928, 388, 8, 2272},
+		{"wioterminal", "examples/pininterrupt", 7387, 1489, 116, 6912},
 
 		// TODO: also check wasm. Right now this is difficult, because
 		// wasm binaries are run through wasm-opt and therefore the
diff --git a/src/runtime/scheduler_cooperative.go b/src/runtime/scheduler_cooperative.go
index bf6f5aec49..274daa84d5 100644
--- a/src/runtime/scheduler_cooperative.go
+++ b/src/runtime/scheduler_cooperative.go
@@ -77,7 +77,6 @@ func addSleepTask(t *task.Task, duration timeUnit) {
 			panic("runtime: addSleepTask: expected next task to be nil")
 		}
 	}
-	t.Data = uint64(duration)
 	now := ticks()
 	if sleepQueue == nil {
 		scheduleLog("  -> sleep new queue")
@@ -85,6 +84,7 @@ func addSleepTask(t *task.Task, duration timeUnit) {
 		// set new base time
 		sleepQueueBaseTime = now
 	}
+	t.Data = uint64(duration + (now - sleepQueueBaseTime))
 
 	// Add to sleep queue.
 	q := &sleepQueue