diff --git a/CMakeLists.txt b/CMakeLists.txt
index ea3f693..d61f991 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -36,6 +36,13 @@ set_property(TARGET wonderswan PROPERTY CXX_STANDARD 98)
 target_compile_definitions(wonderswan PUBLIC VERSION="${VERSION}")
 target_include_directories(wonderswan PUBLIC source)
 
+add_custom_command(
+        TARGET wonderswan POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy
+        ${CMAKE_SOURCE_DIR}/irom_stub/*.bin
+        ${CMAKE_CURRENT_BINARY_DIR}/
+)
+
 add_subdirectory(source)
 
 target_link_libraries(wonderswan wswan glfw ${OPENGL_glu_LIBRARY} ${OPENGL_gl_LIBRARY})
diff --git a/irom_stub/Makefile b/irom_stub/Makefile
new file mode 100644
index 0000000..28de77a
--- /dev/null
+++ b/irom_stub/Makefile
@@ -0,0 +1,20 @@
+.PHONY: all clean
+
+all: ws_irom.bin wsc_irom.bin wc_irom.bin
+	
+clean:
+	@echo " RM"
+	@rm -f *.bin	
+
+ws_irom.bin: irom_stub.asm
+	@echo " AS $@"
+	@nasm $^ -o $@ -DWONDERSWAN=1
+
+wsc_irom.bin: irom_stub.asm
+	@echo " AS $@"
+	@nasm $^ -o $@ -DWONDERSWANCOLOR=1
+	
+wc_irom.bin: irom_stub.asm
+	@echo " AS $@"
+	@nasm $^ -o $@ -DSWANCRYSTAL=1
+	
diff --git a/irom_stub/irom_stub.asm b/irom_stub/irom_stub.asm
new file mode 100644
index 0000000..60f9310
--- /dev/null
+++ b/irom_stub/irom_stub.asm
@@ -0,0 +1,104 @@
+; WonderSwan Internal ROM Stub
+; --------------------------------------
+; Version 1.0
+
+; This is a replacement for the internal rom to prevent using/including any copyrighted material.
+; It does nothing, just lauching the cartridge.
+; It may later include a bootsplah.
+
+%ifdef WONDERSWAN
+%define ROM_SIZE 4096
+%define ROM_SEG 0FF00h
+%else
+%define ROM_SIZE 8192
+%define ROM_SEG 0FE00h
+%endif
+
+; Setup NASM for a 80186
+	bits 16
+	cpu  186
+
+	org 0000h
+    
+%define JUMPER_LOCATION 0000h:0400h
+; ---------------------------------------------------------------------------------------------
+; Boot ROM jumper
+; ---------------------------------------------------------------------------------------------
+; Lock the bootrom
+; Clear a bit of itself
+; Jump to FFFF:FFF0
+; 
+; Must be copied to 0000:0400 then jmp 0000:0400
+ram_jumper:
+    
+    ; Lock the boot rom away
+    IN al, 0A0h
+    OR al, 001h ; Bit 0 lock the boot rom
+    out 0A0h, al
+    
+    mov ax, cs
+    mov es, ax
+    mov di, 0400h
+    mov cx, (.rm_te_end - ram_jumper)
+    xor ax, ax
+    xor bx, bx
+.rm_te_end:
+    rep stosb
+    jmp 0FFFFh:00000h
+ram_jumper_end:
+
+_start:
+    cli
+    cld
+    push cs
+    pop ds
+    xor ax, ax
+    mov es, ax
+
+    ; Clear the IRAM
+    mov     di, 0
+    mov     cx, 16384
+    xor     al, al
+    rep stosb           ; STOSB -> ES:DI
+
+    ; Copy the jumper
+    mov     si, ram_jumper
+    mov     cx, (ram_jumper_end - ram_jumper)
+    mov     di, 0400h
+    xor     ax, ax
+    mov     es, ax
+    rep movsb         ; DS:SI -> ES:DI
+
+    ; Do some register cleanup
+    mov     al, 0FFh
+    out     0C0h, al
+    out     0C1h, al
+    out     0C2h, al
+    xor     ax, ax
+    xor     cx, cx
+    xor     dx, dx
+    mov     ds, ax
+    mov     es, ax
+
+    ; Jump to the jumper!
+    jmp JUMPER_LOCATION
+    
+%ifdef WONDERSWAN
+    db "WonderSwan"
+%elifdef WONDERSWANCOLOR
+    db "WonderSwan Color"
+%elifdef SWANCRYSTAL
+    db "WonderSwan Crystal"
+%else
+%endif
+    db " internal ROM Stub for NewOswan (c)2021 986-Studio"
+; Create at the end of the block, add padding if needed
+TIMES (ROM_SIZE - 16) - ($-$$) DB 0FFh
+
+    jmp ROM_SEG:_start              ; 0
+    db 00        ; ??               ; 5
+    db 0F0h      ; Dev ID           ; 6
+    db 00        ; Min Swan type    ; 7
+    db 00000100b ; flags            ; C
+    db 01        ; No RTC           ; D
+    dw 0FFFFh    ; CRC (need to update it after, but as not used by the rom, no need for now)
\ No newline at end of file
diff --git a/irom_stub/wc_irom.bin b/irom_stub/wc_irom.bin
new file mode 100644
index 0000000..4e0b5aa
Binary files /dev/null and b/irom_stub/wc_irom.bin differ
diff --git a/irom_stub/ws_irom.bin b/irom_stub/ws_irom.bin
new file mode 100644
index 0000000..5e44ed5
Binary files /dev/null and b/irom_stub/ws_irom.bin differ
diff --git a/irom_stub/wsc_irom.bin b/irom_stub/wsc_irom.bin
new file mode 100644
index 0000000..21d04e8
Binary files /dev/null and b/irom_stub/wsc_irom.bin differ