diff --git a/Makefile b/Makefile
index c334fa2..0639b66 100644
--- a/Makefile
+++ b/Makefile
@@ -1,23 +1,16 @@
 OPT = -Os
 
-all: main.nds
-
-res/%.h: res/%.data
-	$(BUILD_BINARY_H)
-
-res/%.pal.h: res/%.data.pal
-	$(BUILD_BINARY_H)
-
-MAIN_OBJ = \
+OBJ = \
 	header.o \
-	start.o \
-	main.o \
-	res/player.data.o \
-	res/player.data.pal.o \
-	res/bowser.data.o \
-	res/bowser.data.pal.o
+	arm9/arm9.bin.o \
+	arm7/arm7.bin.o
 
-main.elf: $(MAIN_OBJ)
+all: cartridge.bin
 
-include arm9.mk
+cartridge.elf: $(OBJ)
+
+TARGET = arm-none-eabi-
+AARCH = -march=armv4t -mlittle-endian
+OBJARCH = -O elf32-littlearm -B armv4t
+LDSCRIPT = cartridge.lds
 include common.mk
diff --git a/arm7/Makefile b/arm7/Makefile
new file mode 100644
index 0000000..66dcf88
--- /dev/null
+++ b/arm7/Makefile
@@ -0,0 +1,11 @@
+OPT = -Os
+
+OBJ = \
+	start.o
+
+all: arm7.bin
+
+arm7.elf: $(OBJ)
+
+include arm7.mk
+include ../common.mk
diff --git a/arm7/arm7.lds b/arm7/arm7.lds
new file mode 100644
index 0000000..5c09ee8
--- /dev/null
+++ b/arm7/arm7.lds
@@ -0,0 +1,50 @@
+OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
+OUTPUT_ARCH(arm)
+MEMORY
+{
+  ram : ORIGIN = 0x02000000, LENGTH = 4M
+}
+SECTIONS
+{
+  . = ORIGIN(ram) + 0x8000;
+
+  .text ALIGN(4) :
+  {
+    KEEP(*(.text.start))
+    *(.text)
+    *(.text.*)
+    *(.glue_7t)
+    *(.glue_7)
+    *(.vfp11_veneer)
+    *(.v4_bx)
+  } > ram
+
+  .data ALIGN(4) :
+  {
+    *(.data)
+    *(.data.*)
+  } > ram
+
+  .rodata ALIGN(4) :
+  {
+    *(.rodata)
+    *(.rodata.*)
+  } > ram
+
+  .ctors ALIGN(4) :
+  {
+    KEEP(*(.ctors))
+    KEEP(*(.ctors.*))
+  } > ram
+
+  .bss ALIGN(4) (NOLOAD) :
+  {
+    *(.bss)
+    *(.bss.*)
+    *(COMMON)
+  } > ram
+
+  INCLUDE "../debug.lds"
+}
+
+INCLUDE "../symbols.lds"
diff --git a/arm7/arm7.mk b/arm7/arm7.mk
new file mode 100644
index 0000000..86e64a5
--- /dev/null
+++ b/arm7/arm7.mk
@@ -0,0 +1,5 @@
+TARGET = arm-none-eabi-
+AARCH = -march=armv4t -mlittle-endian
+CARCH = -march=armv4t -mtune=arm7tdmi -mlittle-endian -mno-thumb-interwork
+OBJARCH = -O elf32-littlearm -B armv4t
+LDSCRIPT = arm7.lds
diff --git a/arm7/start.s b/arm7/start.s
new file mode 100644
index 0000000..62a5724
--- /dev/null
+++ b/arm7/start.s
@@ -0,0 +1,4 @@
+	.section .text.start
+	.global _start
+_start:
+	b _start
diff --git a/arm9/Makefile b/arm9/Makefile
new file mode 100644
index 0000000..85797a7
--- /dev/null
+++ b/arm9/Makefile
@@ -0,0 +1,18 @@
+OPT = -Os
+
+OBJ = \
+	start.o \
+	main.o \
+	../res/player.data.o \
+	../res/player.data.pal.o \
+	../res/bowser.data.o \
+	../res/bowser.data.pal.o
+
+all: arm9.bin
+
+arm9.elf: $(OBJ)
+
+CFLAGS += -I../include
+
+include arm9.mk
+include ../common.mk
diff --git a/addresses_arm9.lds b/arm9/addresses.lds
similarity index 100%
rename from addresses_arm9.lds
rename to arm9/addresses.lds
diff --git a/arm9.lds b/arm9/arm9.lds
similarity index 58%
rename from arm9.lds
rename to arm9/arm9.lds
index 9978cd9..e0832c2 100644
--- a/arm9.lds
+++ b/arm9/arm9.lds
@@ -2,63 +2,50 @@ OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
 OUTPUT_ARCH(arm)
 MEMORY
 {
-  rom : ORIGIN = 0x00000000, LENGTH = 4M
   ram : ORIGIN = 0x02000000, LENGTH = 4M
 }
 SECTIONS
 {
-  . = ORIGIN(rom);
-
-  .text.header ALIGN(4) :
-  {
-    KEEP(*(.text.header))
-  } > rom
-
   . = ORIGIN(ram);
 
-  .text.arm7 ALIGN(4) :
-  {
-    KEEP(*(.text.7start))
-  } > ram AT> rom
-
   .text ALIGN(4) :
   {
-    KEEP(*(.text.9start))
+    KEEP(*(.text.start))
     *(.text)
     *(.text.*)
     *(.glue_7t)
     *(.glue_7)
     *(.vfp11_veneer)
     *(.v4_bx)
-  } > ram AT> rom
+  } > ram
 
   .data ALIGN(4) :
   {
     *(.data)
     *(.data.*)
-  } > ram AT> rom
+  } > ram
 
   .rodata ALIGN(4) :
   {
     *(.rodata)
     *(.rodata.*)
-  } > ram AT> rom
+  } > ram
 
   .ctors ALIGN(4) :
   {
     KEEP(*(.ctors))
     KEEP(*(.ctors.*))
-  } > ram AT> rom
+  } > ram
 
   .bss ALIGN(4) (NOLOAD) :
   {
     *(.bss)
     *(.bss.*)
     *(COMMON)
-  } > ram AT> rom
+  } > ram
 
-  INCLUDE "debug.lds"
+  INCLUDE "../debug.lds"
 }
 
-INCLUDE "symbols.lds"
-INCLUDE "addresses_arm9.lds"
+INCLUDE "../symbols.lds"
+INCLUDE "addresses.lds"
diff --git a/arm9.mk b/arm9/arm9.mk
similarity index 100%
rename from arm9.mk
rename to arm9/arm9.mk
diff --git a/main.c b/arm9/main.c
similarity index 95%
rename from main.c
rename to arm9/main.c
index 1e07c86..4a18f65 100644
--- a/main.c
+++ b/arm9/main.c
@@ -5,10 +5,10 @@
 #include "obj.h"
 #include "oam.h"
 
-#include "res/player.h"
-#include "res/player.pal.h"
-#include "res/bowser.h"
-#include "res/bowser.pal.h"
+#include "../res/player.data.h"
+#include "../res/player.data.pal.h"
+#include "../res/bowser.data.h"
+#include "../res/bowser.data.pal.h"
 
 static inline uint16_t rgb565(const uint8_t * buf)
 {
@@ -430,23 +430,23 @@ void main()
     | DISPCNT__character_obj_mapping_mode__1d_mapping
     ;
 
-  uint32_t pal_size = (uint32_t)&_binary_res_player_data_pal_size;
-  const uint8_t * pal = (const uint8_t *)&_binary_res_player_data_pal_start;
+  uint32_t pal_size = (uint32_t)&_binary_player_data_pal_size;
+  const uint8_t * pal = (const uint8_t *)&_binary_player_data_pal_start;
 
   // palette ram
   for (int i = 0; i < 15; i++) {
     palette_ram.a.bg.palette[0].color[i] = rgb565(&pal[i * 3]);
   }
 
-  uint32_t b_pal_size = (uint32_t)&_binary_res_bowser_data_pal_size;
-  const uint8_t * b_pal = (const uint8_t *)&_binary_res_bowser_data_pal_start;
+  uint32_t b_pal_size = (uint32_t)&_binary_bowser_data_pal_size;
+  const uint8_t * b_pal = (const uint8_t *)&_binary_bowser_data_pal_start;
 
   // bowser palette ram
   for (int i = 0; i < 16; i++) {
     palette_ram.b.obj.palette[0].color[i] = rgb565(&b_pal[i * 3]);
   }
 
-  const uint8_t * data = (const uint8_t *)&_binary_res_player_data_start;
+  const uint8_t * data = (const uint8_t *)&_binary_player_data_start;
 
   for (int y = 0; y < 48; y++) {
     uint8_t a = data[y * 8 + 7];
@@ -479,7 +479,7 @@ void main()
   bg_vram.a.screen.offset[0].block[31].u16[32 * 1 + 1] = 4;
   bg_vram.a.screen.offset[0].block[31].u16[32 * 2 + 1] = 5;
 
-  const uint8_t * b_data = (const uint8_t *)&_binary_res_bowser_data_start;
+  const uint8_t * b_data = (const uint8_t *)&_binary_bowser_data_start;
 
   for (int c_y = 0; c_y < 8; c_y++) {
     for (int c_x = 0; c_x < 8; c_x++) {
diff --git a/start.s b/arm9/start.s
similarity index 90%
rename from start.s
rename to arm9/start.s
index d0783ae..a534ca5 100644
--- a/start.s
+++ b/arm9/start.s
@@ -22,7 +22,7 @@ _fill_loop.\@:
 _fill_break.\@:
         .endm
 
-        .section .text.9start
+        .section .text.start
         .global _start
 _start:
 	/*
@@ -52,14 +52,8 @@ _link_bss:
 
 _c_runtime:
 	/* set stack pointer */
-        ldr sp, =0x23ffffc
+        ldr sp, =__stack_end
 
 	/* jump to main */
         ldr r0, =main
         bx r0
-
-	.section .text.7start
-	.global _7start
-_7start:
-	mov r1, #0x7
-	b _7start
diff --git a/cartridge.lds b/cartridge.lds
new file mode 100644
index 0000000..6b5d256
--- /dev/null
+++ b/cartridge.lds
@@ -0,0 +1,51 @@
+OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
+OUTPUT_ARCH(arm)
+MEMORY
+{
+  rom : ORIGIN = 0x00000000, LENGTH = 4M
+}
+SECTIONS
+{
+  . = 0x00000000;
+
+  _start = .;
+
+  .text.header ALIGN(4) :
+  {
+    KEEP(*(.text.header))
+  } AT>rom
+
+  . = 0x02000000;
+
+  .text.arm9 ALIGN(4) :
+  {
+    KEEP(arm9/arm9.bin.o(*))
+  } AT>rom
+
+  . = 0x02000000 + 0x8000;
+
+  .text.arm7 ALIGN(4) :
+  {
+    KEEP(arm7/arm7.bin.o(*))
+  } AT>rom
+
+  /DISCARD/ :
+  {
+  *(.glue_7) *(.glue_7t) *(.vfp11_veneer) *(.v4_bx)
+  *(.ARM.attributes) *(.iplt) *(.rel.iplt) *(.igot.plt)
+  }
+}
+
+/* header symbols */
+_arm9_offset = LOADADDR(.text.arm9);
+_arm9_entry = ADDR(.text.arm9);
+_arm9_addr = ADDR(.text.arm9);
+_arm9_size = SIZEOF(.text.arm9);
+
+_arm7_offset = LOADADDR(.text.arm7);
+_arm7_entry = ADDR(.text.arm7);
+_arm7_addr = ADDR(.text.arm7);
+_arm7_size = SIZEOF(.text.arm7);
+
+_rom_size = SIZEOF(.text.header) + SIZEOF(.text.arm9) + SIZEOF(.text.arm7);
+_header_size = SIZEOF(.text.header);
diff --git a/common.mk b/common.mk
index e8d8c27..aaba43c 100644
--- a/common.mk
+++ b/common.mk
@@ -80,6 +80,12 @@ endef
 
 -include $(shell find -type f -name '*.d')
 
+clean:
+	find -P \
+		-regextype posix-egrep \
+		-regex '.*\.(nds|o|d|bin|elf|gch)$$' \
+		-exec rm {} \;
+
 .SUFFIXES:
 .INTERMEDIATE:
 .SECONDARY:
diff --git a/header.s b/header.s
index b8ebb76..01e9fff 100644
--- a/header.s
+++ b/header.s
@@ -1,7 +1,7 @@
 	.section .text.header
 
-	.fill 12,1,0x0    /* Game Title */
-	.ascii "CODE"     /* Game Code */
+	.ascii "game title  " /* Game Title */
+	.ascii "NTR1"     /* Game Code */
 	.ascii "00"       /* Maker Code */
 	.byte 0x0         /* Unit Code */
 	.byte 0x0         /* Encryption Seed Select */
@@ -30,7 +30,7 @@
 	.long 0x00586000  /* 040001a4 setting for normal commands */
 	.long 0x001808F8  /* 040001a4 setting for KEY1 commands */
 	.long 0x00000000  /* Icon/Title offset */
-	.short 0x8e6e 	  /* Secure Area Checksum */
+	.short 0x4bff 	  /* Secure Area Checksum */
 	.short 0x0d7e     /* Secure Area Delay */
 	.long 0x02000a58  /* ARM9 auto load list hook ram address */
 	.long 0x02380158  /* ARM7 auto load list hook ram address */
diff --git a/bg.h b/include/bg.h
similarity index 100%
rename from bg.h
rename to include/bg.h
diff --git a/bits.h b/include/bits.h
similarity index 100%
rename from bits.h
rename to include/bits.h
diff --git a/graphics_engine_a.h b/include/graphics_engine_a.h
similarity index 100%
rename from graphics_engine_a.h
rename to include/graphics_engine_a.h
diff --git a/graphics_engine_b.h b/include/graphics_engine_b.h
similarity index 100%
rename from graphics_engine_b.h
rename to include/graphics_engine_b.h
diff --git a/io_registers.h b/include/io_registers.h
similarity index 100%
rename from io_registers.h
rename to include/io_registers.h
diff --git a/oam.h b/include/oam.h
similarity index 100%
rename from oam.h
rename to include/oam.h
diff --git a/obj.h b/include/obj.h
similarity index 100%
rename from obj.h
rename to include/obj.h
diff --git a/palette.h b/include/palette.h
similarity index 100%
rename from palette.h
rename to include/palette.h
diff --git a/patch.py b/patch.py
index 33819f4..2281d7e 100644
--- a/patch.py
+++ b/patch.py
@@ -43,11 +43,14 @@ assert buf[0x15c] == 0x56
 assert buf[0x15d] == 0xcf
 
 logo_crc = crc16_modbus(buf[0x0c0:0xc0 + 0x9c])
-print(hex(logo_crc))
+print("logo", hex(logo_crc))
 assert logo_crc == 0xcf56
 
 header_crc = crc16_modbus(buf[0:0x15e])
-print(hex(header_crc))
+print("header", hex(header_crc))
+
+secure_area_crc = crc16_modbus(buf[0x4000:0x8000])
+print("secure area", hex(secure_area_crc))
 
 import struct
 header_crc_b = struct.pack('<H', header_crc)
diff --git a/registers/generate.sh b/registers/generate.sh
index a0126ef..0e09d0b 100644
--- a/registers/generate.sh
+++ b/registers/generate.sh
@@ -1,7 +1,7 @@
 set -eux
 
-python format.py 0x04000000.txt graphics_engine_a 0x1000 > ../graphics_engine_a.h
-python format.py 0x04001000.txt graphics_engine_b 0 > ../graphics_engine_b.h
+python format.py 0x04000000.txt graphics_engine_a 0x1000 > ../include/graphics_engine_a.h
+python format.py 0x04001000.txt graphics_engine_b 0 > ../include/graphics_engine_b.h
 
 make graphics_engine_bits.csv
-python format_bits.py graphics_engine_bits.csv > ../bits.h
+python format_bits.py graphics_engine_bits.csv > ../include/bits.h
diff --git a/res/Makefile b/res/Makefile
new file mode 100644
index 0000000..953252e
--- /dev/null
+++ b/res/Makefile
@@ -0,0 +1,18 @@
+OBJ += $(patsubst %.data,%.data.o,$(wildcard *.data))
+OBJ += $(patsubst %.data.pal,%.data.pal.o,$(wildcard *.data.pal))
+
+HEADER += $(patsubst %.data,%.data.h,$(wildcard *.data))
+HEADER += $(patsubst %.data.pal,%.data.pal.h,$(wildcard *.data.pal))
+
+TARGET=arm-none-eabi-
+OBJARCH=-O elf32-littlearm -B armv5te
+
+all: $(OBJ) $(HEADER)
+
+include ../common.mk
+
+%.data.h: %.data
+	$(BUILD_BINARY_H)
+
+%.data.pal.h: %.data.pal
+	$(BUILD_BINARY_H)
diff --git a/res/bowser.data.h b/res/bowser.data.h
new file mode 100644
index 0000000..1133820
--- /dev/null
+++ b/res/bowser.data.h
@@ -0,0 +1,5 @@
+#pragma once
+#include <stdint.h>
+extern uint32_t _binary_bowser_data_start __asm("_binary_bowser_data_start");
+extern uint32_t _binary_bowser_data_end __asm("_binary_bowser_data_end");
+extern uint32_t _binary_bowser_data_size __asm("_binary_bowser_data_size");
diff --git a/res/bowser.data.pal.h b/res/bowser.data.pal.h
new file mode 100644
index 0000000..c134213
--- /dev/null
+++ b/res/bowser.data.pal.h
@@ -0,0 +1,5 @@
+#pragma once
+#include <stdint.h>
+extern uint32_t _binary_bowser_data_pal_start __asm("_binary_bowser_data_pal_start");
+extern uint32_t _binary_bowser_data_pal_end __asm("_binary_bowser_data_pal_end");
+extern uint32_t _binary_bowser_data_pal_size __asm("_binary_bowser_data_pal_size");
diff --git a/res/bowser.h b/res/bowser.h
deleted file mode 100644
index c7250fe..0000000
--- a/res/bowser.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-#include <stdint.h>
-extern uint32_t _binary_res_bowser_data_start __asm("_binary_res_bowser_data_start");
-extern uint32_t _binary_res_bowser_data_end __asm("_binary_res_bowser_data_end");
-extern uint32_t _binary_res_bowser_data_size __asm("_binary_res_bowser_data_size");
diff --git a/res/bowser.pal.h b/res/bowser.pal.h
deleted file mode 100644
index 234d723..0000000
--- a/res/bowser.pal.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-#include <stdint.h>
-extern uint32_t _binary_res_bowser_data_pal_start __asm("_binary_res_bowser_data_pal_start");
-extern uint32_t _binary_res_bowser_data_pal_end __asm("_binary_res_bowser_data_pal_end");
-extern uint32_t _binary_res_bowser_data_pal_size __asm("_binary_res_bowser_data_pal_size");
diff --git a/res/player.data.h b/res/player.data.h
new file mode 100644
index 0000000..430fcaa
--- /dev/null
+++ b/res/player.data.h
@@ -0,0 +1,5 @@
+#pragma once
+#include <stdint.h>
+extern uint32_t _binary_player_data_start __asm("_binary_player_data_start");
+extern uint32_t _binary_player_data_end __asm("_binary_player_data_end");
+extern uint32_t _binary_player_data_size __asm("_binary_player_data_size");
diff --git a/res/player.data.pal.h b/res/player.data.pal.h
new file mode 100644
index 0000000..873735e
--- /dev/null
+++ b/res/player.data.pal.h
@@ -0,0 +1,5 @@
+#pragma once
+#include <stdint.h>
+extern uint32_t _binary_player_data_pal_start __asm("_binary_player_data_pal_start");
+extern uint32_t _binary_player_data_pal_end __asm("_binary_player_data_pal_end");
+extern uint32_t _binary_player_data_pal_size __asm("_binary_player_data_pal_size");
diff --git a/res/player.h b/res/player.h
deleted file mode 100644
index 9e3857d..0000000
--- a/res/player.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-#include <stdint.h>
-extern uint32_t _binary_res_player_data_start __asm("_binary_res_player_data_start");
-extern uint32_t _binary_res_player_data_end __asm("_binary_res_player_data_end");
-extern uint32_t _binary_res_player_data_size __asm("_binary_res_player_data_size");
diff --git a/res/player.pal.h b/res/player.pal.h
deleted file mode 100644
index 8e3ada5..0000000
--- a/res/player.pal.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-#include <stdint.h>
-extern uint32_t _binary_res_player_data_pal_start __asm("_binary_res_player_data_pal_start");
-extern uint32_t _binary_res_player_data_pal_end __asm("_binary_res_player_data_pal_end");
-extern uint32_t _binary_res_player_data_pal_size __asm("_binary_res_player_data_pal_size");
diff --git a/symbols.lds b/symbols.lds
index 475a96e..d4e530d 100644
--- a/symbols.lds
+++ b/symbols.lds
@@ -17,17 +17,3 @@ __ctors_link_end = ADDR(.ctors) + SIZEOF(.ctors);
 
 __bss_link_start = ADDR(.bss);
 __bss_link_end = ADDR(.bss) + SIZEOF(.bss);
-
-/* header symbols */
-_arm9_offset = LOADADDR(.text);
-_arm9_entry = ADDR(.text);
-_arm9_addr = ADDR(.text);
-_arm9_size = SIZEOF(.text) + SIZEOF(.data) + SIZEOF(.rodata) + SIZEOF(.ctors);
-
-_arm7_offset = LOADADDR(.text.arm7);
-_arm7_entry = ADDR(.text.arm7);
-_arm7_addr = ADDR(.text.arm7);
-_arm7_size = SIZEOF(.text.arm7);
-
-_rom_size = SIZEOF(.text.header) + SIZEOF(.text) + SIZEOF(.data) + SIZEOF(.rodata) + SIZEOF(.ctors) + SIZEOF(.text.arm7);
-_header_size = SIZEOF(.text.header);