diff --git a/config/env.mk b/config/env.mk
index 95afe03..ff30b3b 100644
--- a/config/env.mk
+++ b/config/env.mk
@@ -22,15 +22,12 @@
 #                                       #
 #########################################
 
-# use custom gcc | true or false
-USE_CUST_GCC ?= false
-
-# custom gcc ext (if used)
-CUST_GCC ?= 
-
 # addionital gcc flags
 EXTRA_GCC_FLAGS ?= 
 
+# arch config. 32-bit = armv7a | 64-bit = aarch64 | default = aarch64
+TARGET_BUILD_ARCH := aarch64
+
 # debugging mode (binary)
 ENABLE_BINARY_DEBUGGING ?= false
 
@@ -45,13 +42,6 @@ ENABLE_BINARY_DEBUGGING ?= false
 #                                       #
 #########################################
 
-# gcc setting
-ifeq ($(USE_CUST_GCC), true)
-	CC ?= $(CUST_GCC)
-else ifeq ($(USE_CUST_GCC), false)
-	CC ?= gcc
-endif
-
 # gcc flag settings
 ifeq ($(ENABLE_BINARY_DEBUGGING), true)
 	CFLAGS ?= -O3 -g -Wall -Wextra $(EXTRA_GCC_FLAGS)