diff --git a/drv/bkp_regs.h b/drv/bkp_regs.h
index 8a3b6c7..8101c15 100644
--- a/drv/bkp_regs.h
+++ b/drv/bkp_regs.h
@@ -62,6 +62,7 @@ union BKP_CSR {
 };
 
 struct BKP {
+	uint32_t reserved1;
 	union BKP_DR DR[20];
 	union BKP_RTCCR RTCCR;
 	union BKP_CR CR;