diff --git a/spi4ba.h b/spi4ba.h
index 8a01792..a0316bc 100644
--- a/spi4ba.h
+++ b/spi4ba.h
@@ -114,5 +114,6 @@
 int spi_block_erase_5c_4ba_direct(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
 int spi_block_erase_dc_4ba_direct(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
 
+int spi_write_extended_address_register(struct flashctx *flash, uint8_t regdata);
 
 #endif /* __SPI_4BA_H__ */