diff --git a/drivers/spi/spi-airoha-snfi.c b/drivers/spi/spi-airoha-snfi.c
index 437ab6745b1a..8408aee9c06e 100644
--- a/drivers/spi/spi-airoha-snfi.c
+++ b/drivers/spi/spi-airoha-snfi.c
@@ -776,7 +776,11 @@ static ssize_t airoha_snand_dirmap_write(struct spi_mem_dirmap_desc *desc,
 		return -EOPNOTSUPP;
 	}
 
+	if (offs > 0)
+		memset(txrx_buf, 0xff, offs);
 	memcpy(txrx_buf + offs, buf, len);
+	if (bytes > offs + len)
+		memset(txrx_buf + offs + len, 0xff, bytes - offs - len);
 
 	err = airoha_snand_set_mode(as_ctrl, SPI_MODE_DMA);
 	if (err < 0)