diff --git a/include/drivers/fwu/fwu.h b/include/drivers/fwu/fwu.h
index 489d4a1..18e8a31 100644
--- a/include/drivers/fwu/fwu.h
+++ b/include/drivers/fwu/fwu.h
@@ -13,8 +13,11 @@
 #define FWU_BANK_STATE_VALID		0xFEU
 #define FWU_BANK_STATE_INVALID		0xFFU
 
+#define INVALID_BOOT_IDX		0xFFFFFFFFU
+
 void fwu_init(void);
 uint32_t fwu_get_active_bank_state(void);
+uint32_t fwu_get_alternate_boot_bank(void);
 const struct fwu_metadata *fwu_get_metadata(void);
 
 #endif /* FWU_H */