diff --git a/boot/zephyr/boot_serial_extension_zephyr_basic.c b/boot/zephyr/boot_serial_extension_zephyr_basic.c
index b0c75f4a7..e0f978adf 100644
--- a/boot/zephyr/boot_serial_extension_zephyr_basic.c
+++ b/boot/zephyr/boot_serial_extension_zephyr_basic.c
@@ -47,7 +47,7 @@ static int bs_custom_storage_erase(const struct nmgr_hdr *hdr,
     if (rc < 0) {
         BOOT_LOG_ERR("failed to open flash area");
     } else {
-        rc = flash_area_erase(fa, 0, flash_area_get_size(fa));
+        rc = flash_area_flatten(fa, 0, flash_area_get_size(fa));
         if (rc < 0) {
             BOOT_LOG_ERR("failed to erase flash area");
         }