diff --git a/plugins/superio/fu-superio-device.c b/plugins/superio/fu-superio-device.c
index 5533f9e8d..b90e2543a 100644
--- a/plugins/superio/fu-superio-device.c
+++ b/plugins/superio/fu-superio-device.c
@@ -202,7 +202,7 @@ fu_superio_device_ec_write1 (FuSuperioDevice *self, guint8 data, GError **error)
 	return fu_superio_outb (priv->fd, priv->pm1_iobad1, data, error);
 }
 
-gboolean
+static gboolean
 fu_superio_device_ec_flush (FuSuperioDevice *self, GError **error)
 {
 	FuSuperioDevicePrivate *priv = GET_PRIVATE (self);
@@ -332,6 +332,12 @@ fu_superio_device_setup (FuDevice *device, GError **error)
 					 &priv->pm1_iobad1, error))
 		return FALSE;
 
+	/* drain */
+	if (!fu_superio_device_ec_flush (self, error)) {
+		g_prefix_error (error, "failed to flush: ");
+		return FALSE;
+	}
+
 	/* dump PMC register map */
 	if (g_getenv ("FWUPD_SUPERIO_VERBOSE") != NULL) {
 		guint8 buf[0xff] = { 0x00 };
diff --git a/plugins/superio/fu-superio-device.h b/plugins/superio/fu-superio-device.h
index 38023cf97..88f4d5ed0 100644
--- a/plugins/superio/fu-superio-device.h
+++ b/plugins/superio/fu-superio-device.h
@@ -20,8 +20,6 @@ struct _FuSuperioDeviceClass
 						 GError		**error);
 };
 
-gboolean	 fu_superio_device_ec_flush	(FuSuperioDevice	*self,
-						 GError			**error);
 gboolean	 fu_superio_device_ec_read	(FuSuperioDevice	*self,
 						 guint8			*data,
 						 GError			**error);
diff --git a/plugins/superio/fu-superio-it85-device.c b/plugins/superio/fu-superio-it85-device.c
index 33372175a..9859ee9b8 100644
--- a/plugins/superio/fu-superio-it85-device.c
+++ b/plugins/superio/fu-superio-it85-device.c
@@ -41,10 +41,6 @@ fu_superio_it85_device_setup (FuSuperioDevice *self, GError **error)
 	g_autofree gchar *version = NULL;
 
 	/* get EC size */
-	if (!fu_superio_device_ec_flush (self, error)) {
-		g_prefix_error (error, "failed to flush: ");
-		return FALSE;
-	}
 	if (!fu_superio_device_ec_get_param (self, 0xe5, &size_tmp, error)) {
 		g_prefix_error (error, "failed to get EC size: ");
 		return FALSE;
diff --git a/plugins/superio/fu-superio-it89-device.c b/plugins/superio/fu-superio-it89-device.c
index 817acb1c6..6a7d8c4b2 100644
--- a/plugins/superio/fu-superio-it89-device.c
+++ b/plugins/superio/fu-superio-it89-device.c
@@ -102,10 +102,6 @@ fu_superio_it89_device_setup (FuSuperioDevice *self, GError **error)
 	}
 
 	/* get version */
-	if (!fu_superio_device_ec_flush (self, error)) {
-		g_prefix_error (error, "failed to flush: ");
-		return FALSE;
-	}
 	if (!fu_superio_device_ec_get_param (self, 0x00, &version_tmp[0], error)) {
 		g_prefix_error (error, "failed to get version major: ");
 		return FALSE;