diff --git a/boot/zephyr/Kconfig.serial_recovery b/boot/zephyr/Kconfig.serial_recovery
index 0a41abf..92d0da0 100644
--- a/boot/zephyr/Kconfig.serial_recovery
+++ b/boot/zephyr/Kconfig.serial_recovery
@@ -54,6 +54,7 @@
 config BOOT_SERIAL_UNALIGNED_BUFFER_SIZE
 	int "Stack buffer for unaligned memory writes"
 	default 64
+	range 0 128
 	help
 	  Specifies the stack usage for a buffer which is used for unaligned
 	  memory access when data is written to a device with memory alignment