diff --git a/boot/zephyr/include/mcuboot-mbedtls-cfg.h b/boot/zephyr/include/mcuboot-mbedtls-cfg.h
index 2bab537..02bf0b0 100644
--- a/boot/zephyr/include/mcuboot-mbedtls-cfg.h
+++ b/boot/zephyr/include/mcuboot-mbedtls-cfg.h
@@ -25,6 +25,7 @@
 #include "config-rsa.h"
 #elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256) || \
       defined(CONFIG_BOOT_ENCRYPT_EC256) || \
+      defined(CONFIG_BOOT_SERIAL_ENCRYPT_EC256) || \
       (defined(CONFIG_BOOT_ENCRYPT_X25519) && !defined(CONFIG_BOOT_SIGNATURE_TYPE_ED25519))
 #include "config-asn1.h"
 #elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ED25519)