diff --git a/arm9/source/game/tadx.c b/arm9/source/game/tadx.c
new file mode 100644
index 0000000..cf4064b
--- /dev/null
+++ b/arm9/source/game/tadx.c
@@ -0,0 +1,15 @@
+#include "tadx.h"
+#include "cia.h"
+
+u32 ValidateTadXHeader(TadXHeader* header) {
+	// super strict validation
+    if ((getbe32(header->size_header) != TADX_HEADER_SIZE) ||
+        (getbe32(header->size_cert) != TADX_CERT_SIZE) ||
+        (getbe32(header->size_ticket) != TICKET_TWL_SIZE) ||
+        (getbe32(header->size_tmd) != TMD_SIZE_TWL) ||
+        (getbe32(header->reserved0) != 0) ||
+        (getbe32(header->reserved1) != 0) ||
+        (getbe32(header->size_content) == 0))
+        return 1;
+    return 0;
+}
diff --git a/arm9/source/game/tadx.h b/arm9/source/game/tadx.h
new file mode 100644
index 0000000..adb7c41
--- /dev/null
+++ b/arm9/source/game/tadx.h
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "common.h"
+#include "ticket.h"
+#include "tmd.h"
+
+#define TADX_HEADER_SIZE    sizeof(TadXHeader)
+#define TADX_CERT_SIZE     	0xE80
+
+#define TADX_OFFSET_CERT	align(TADX_HEADER_SIZE, 40)
+#define TADX_OFFSET_TICKET	(TADX_OFFSET_CERT   + align(TADX_CERT_SIZE, 40))
+#define TADX_OFFSET_TMD		(TADX_OFFSET_TICKET + align(TICKET_TWL_SIZE, 40))
+#define TADX_OFFSET_CONTENT	(TADX_OFFSET_TMD    + align(TMD_SIZE_TWL, 40))
+#define TADX_OFFSET_CHUNK	(TADX_OFFSET_TMD    + TMD_SIZE_STUB)
+
+// this describes the TWL TAD exchangable format (similar to CIA)
+// see: https://wiibrew.org/wiki/WAD_files#WAD_format
+typedef struct {
+    u8 size_header[4];
+    u8 type[2];
+    u8 version[2];
+    u8 size_cert[4];
+    u8 reserved0[4];
+    u8 size_ticket[4];
+    u8 size_tmd[4];
+    u8 size_content[4];
+    u8 reserved1[4];
+} PACKED_STRUCT TadXHeader;
+
+typedef struct {
+    TadXHeader header;
+    u8 header_padding[0x40 - (TADX_HEADER_SIZE % 0x40)];
+    u8 cert[TADX_CERT_SIZE];
+    // cert is aligned and needs no padding
+    Ticket ticket;
+    u8 ticket_padding[0x40 - (TICKET_TWL_SIZE % 0x40)];
+    u8 tmd[TMD_SIZE_TWL];
+    u8 tmd_padding[0x40 - (TMD_SIZE_TWL % 40)];
+} PACKED_ALIGN(16) TadXStub;