diff --git a/plugins/ccgx/fu-ccgx-firmware.c b/plugins/ccgx/fu-ccgx-firmware.c
index 53790688d..7b5bc7762 100644
--- a/plugins/ccgx/fu-ccgx-firmware.c
+++ b/plugins/ccgx/fu-ccgx-firmware.c
@@ -139,6 +139,17 @@ fu_ccgx_firmware_add_record (FuCcgxFirmware *self, const gchar *line, GError **e
 	return TRUE;
 }
 
+static guint8
+fu_ccgx_firmware_record_calc_checksum (FuCcgxFirmwareRecord *rcd)
+{
+	guint8 csum = 0x0;
+	gsize bufsz = 0;
+	const guint8 *buf = g_bytes_get_data (rcd->data, &bufsz);
+	for (gsize j = 0; j < bufsz; j++)
+		csum += buf[j];
+	return csum;
+}
+
 static gboolean
 fu_ccgx_firmware_parse_md_block (FuCcgxFirmware *self, FuFirmwareImage *img, GError **error)
 {
@@ -198,10 +209,8 @@ fu_ccgx_firmware_parse_md_block (FuCcgxFirmware *self, FuFirmwareImage *img, GEr
 	}
 	for (guint i = 0; i < self->records->len - 1; i++) {
 		rcd = g_ptr_array_index (self->records, i);
-		buf = g_bytes_get_data (rcd->data, &bufsz);
-		fw_size += bufsz;
-		for (gsize j = 0; j < bufsz; j++)
-			checksum_calc += buf[j];
+		checksum_calc += fu_ccgx_firmware_record_calc_checksum (rcd);
+		fw_size += g_bytes_get_size (rcd->data);
 	}
 	if (fw_size != metadata.fw_size)  {
 		g_set_error (error,