diff --git a/package/beecrypt/beecrypt.mk b/package/beecrypt/beecrypt.mk
index 4fcdf439a3..bd29b3b2c8 100644
--- a/package/beecrypt/beecrypt.mk
+++ b/package/beecrypt/beecrypt.mk
@@ -22,6 +22,11 @@ ifeq ($(BR2_m68k_cf),y)
 BEECRYPT_CONF_OPTS += --enable-debug
 endif
 
+# arm asm optimization doesn't work for thumb-only
+ifeq ($(BR2_arm):$(BR2_ARM_CPU_HAS_ARM),y:)
+BEECRYPT_CONF_OPTS += --enable-debug
+endif
+
 ifeq ($(BR2_PACKAGE_BEECRYPT_CPP),y)
 BEECRYPT_DEPENDENCIES += icu
 BEECRYPT_CONF_OPTS += --with-cplusplus