Merge pull request #3 from NinjaCheetah/master

feat: Add workflow to automatically build devsigned SRL and TAD

.github/workflows/build.yml

@@ -19,16 +19,59 @@ jobs:
     name: Build with Docker using devkitARM
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v1
+        uses: actions/checkout@v4
       - name: Setup environment
         run: git config --global safe.directory '*'
       - name: Build TAD Delivery Tool
         run: make
       - name: Publish build to GH Actions
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4.3.6
         with:
-          path: "*.dsi"
-          name: build
+          path: "TDT.dsi"
+          name: TDT-Nightly-Unsigned
+
+  devsign:
+    runs-on: windows-latest
+    needs: [build]
+    name: Devsign TDT and build a TAD
+    steps:
+      - name: Download artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: TDT-Nightly-Unsigned
+          path: D:\a\TDT\TDT\TDT-Build
+      - name: Set up Python 3.12
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - name: Clone ntool
+        uses: GuillaumeFalourd/clone-github-repo-action@v2.1
+        with:
+          depth: 1
+          owner: 'xprism1'
+          repository: 'ntool'
+      - name: Devsign TAD Delivery Tool
+        run: |
+          cp TDT-Build\TDT.dsi ntool
+          cd ntool
+          pip install pycryptodome
+          python ntool.py srl_retail2dev TDT.dsi
+      - name: Publish devsigned build to GH Actions
+        uses: actions/upload-artifact@v4.3.6
+        with:
+          path: "ntool/TDT_dev.srl"
+          name: TDT-Nightly-Devsigned
+      - name: Make a devsigned TAD
+        run: |
+          curl https://cdn.randommeaninglesscharacters.com/tools/maketad/maketad.zip -o maketad.zip
+          7z e maketad.zip
+          cp ntool/TDT_dev.srl .
+          .\maketad-20090604.exe TDT_dev.srl -s -o TDT-Nightly.tad
+      - name: Publish devsigned TAD to GH Actions
+        uses: actions/upload-artifact@v4.3.6
+        with:
+          path: "TDT-Nightly.tad"
+          name: TDT-Nightly-TAD
 
   # Only run this for non-PR jobs.
   publish_build:
@@ -42,8 +85,7 @@ jobs:
         with:
           name: build
           path: build
-      - name: 
-        if: 
+      - name: Publish Build
         run: |
           ID=$(jq --raw-output '.release.id' $GITHUB_EVENT_PATH)
 

.gitignore

@@ -2,7 +2,9 @@
 *.d
 *.nds
 *.tad
+*.wad
 *.dsi
+*.srl
 *.elf
 *.map
 *build/
@@ -10,4 +12,28 @@
 *.DS_Store
 *._*
 
+# For the emulator SD
+*_nds/
+*private/
+*gm9i/
+
+# Test TADs:
+#   00030004
+*BrainAgeExpressArtsAndLetters/
+*BrainAgeExpressMath/
+#   00030005
+*DownloadPlay/
+*PictoChat/
+#   0003000f
+*DSHashTable/
+*sysmenuVersion/
+*wlanfirm/
+#   00030015
+*Settings/
+#   00030017
+*Launcher/
+
+# TWL EVA title check
+*tad_check/
+
 arm9/include/version.h

README.md

@@ -15,6 +15,8 @@ This can modify your internal system NAND! There is *always* a risk of **brickin
 - [DevkitPro](https://devkitpro.org/): devkitARM and libnds
 - [Tuxality](https://github.com/Tuxality): [maketmd](https://github.com/Tuxality/maketmd)
 - [Martin Korth (nocash)](https://problemkaputt.de): [GBATEK](https://problemkaputt.de/gbatek.htm)
-- [Epicpkmn11](https://github.com/Epicpkmn11): [TMFH](https://github.com/Epicpkmn11/NTM) (what this is a fork of)
+- [Epicpkmn11](https://github.com/Epicpkmn11): [NTM](https://github.com/Epicpkmn11/NTM) (what this is a fork of)
 - [JeffRuLz](https://github.com/JeffRuLz): [TMFH](https://github.com/JeffRuLz/TMFH) (what NTM is a fork of)
 - [DesperateProgrammer](https://github.com/DesperateProgrammer): [DSi Language Patcher](https://github.com/DesperateProgrammer/DSiLanguagePacher) (working NAND writing code)
+- [NinjaCheetah](https://github.com/NinjaCheetah): Helping fix some TAD decryption issues
+- [DamiDoop](https://github.com/DamiDoop): Making the very nice icon

arm9/src/install.c

@@ -62,7 +62,7 @@ static bool _iqueHack(tDSiHeader* h)
 {
 	if (!h) return false;
 
-	if (h->ndshdr.reserved1[8] == 0x80)
+	if (h->ndshdr.reserved1[8] == 0x80 && dataTitle == FALSE)
 	{
 		iprintf("iQue Hack...");
 
@@ -81,7 +81,7 @@ static unsigned long long _getSaveDataSize(tDSiHeader* h)
 {
 	unsigned long long size = 0;
 
-	if (h)
+	if (h && dataTitle == FALSE)
 	{
 		size += h->public_sav_size;
 		size += h->private_sav_size;
@@ -154,7 +154,7 @@ static bool _openMenuSlot()
 
 static void _createPublicSav(tDSiHeader* h, char* dataPath)
 {
-	if (!h) return;
+	if (!h || dataTitle == TRUE) return;
 
 	if (h->public_sav_size > 0)
 	{
@@ -199,7 +199,7 @@ static void _createPublicSav(tDSiHeader* h, char* dataPath)
 
 static void _createPrivateSav(tDSiHeader* h, char* dataPath)
 {
-	if (!h) return;
+	if (!h || dataTitle == TRUE) return;
 
 	if (h->private_sav_size > 0)
 	{
@@ -244,7 +244,7 @@ static void _createPrivateSav(tDSiHeader* h, char* dataPath)
 
 static void _createBannerSav(tDSiHeader* h, char* dataPath)
 {
-	if (!h) return;
+	if (!h || dataTitle == TRUE) return;
 
 	if (h->appflags & 0x4)
 	{
@@ -290,7 +290,7 @@ static void _createTicket(tDSiHeader *h, char* ticketPath)
 {
 	if (!h) return;
 
-	iprintf("Forging ticket...");
+	iprintf("Signing ticket...");
 	swiWaitForVBlank();
 
 	if (!ticketPath)
@@ -304,15 +304,11 @@ static void _createTicket(tDSiHeader *h, char* ticketPath)
 		const u32 encryptedSize = sizeof(ticket_v0_t) + 0x20;
 		u8 *buffer = (u8*)memalign(4, encryptedSize); //memalign might be needed for encryption, but not sure
 		memset(buffer, 0, encryptedSize);
-		ticket_v0_t *ticket = (ticket_v0_t*)buffer;
-		ticket->sig_type[0] = 0x00;
-		ticket->sig_type[1] = 0x01;
-		ticket->sig_type[2] = 0x00;
-		ticket->sig_type[3] = 0x01;
-		strcpy(ticket->issuer, "Root-CA00000001-XS00000006");
-		PUT_UINT32_BE(h->tid_high, ticket->title_id, 0);
-		PUT_UINT32_BE(h->tid_low, ticket->title_id, 4);
-		memset(ticket->content_access_permissions, 0xFF, 0x20);
+
+		FILE *ticket = fopen("sd:/_nds/TADDeliveryTool/tmp/temp.tik", "rb");
+    	fseek(ticket, 0, SEEK_SET);
+		fread(buffer, sizeof(u8), sizeof(ticket_v0_t), ticket);
+		fclose(ticket);
 
 		// Encrypt
 		if (dsi_es_block_crypt(buffer, encryptedSize, ENCRYPT) != 0)
@@ -391,7 +387,9 @@ bool install(char* tadPath, bool systemTitle)
 			h->tid_high == 0x0003000f || // Data titles
 			h->tid_high == 0x00030015 || // System titles
 			h->tid_high == 0x00030017)   // Launcher
-		{}
+		{} else if (dataTitle == TRUE) {
+			iprintf("TAD is a data title. ");
+		}
 		else
 		{
 			iprintf("\x1B[31m");	//red
@@ -439,8 +437,13 @@ bool install(char* tadPath, bool systemTitle)
 			goto error;
 		}
 
-		//blacklisted titles
+		/*
+		// Blacklisted titles
+		//
+		// I'm disabling this because if you can reinstall wlanfirm then it's silly to block the camera app...
+		// The app has shown itself to be safe enough, and soon hopefully will get legit installs for some TADs.
 		{
+
 			//tid without region
 			u32 tidLow = (h->tid_low & 0xFFFFFF00);
 			if (!sdnandMode && (
@@ -474,19 +477,24 @@ bool install(char* tadPath, bool systemTitle)
 				}
 			}
 		}
+		*/
 
 		//confirmation message
 		{
 			const char system[] = "\x1B[41mWARNING:\x1B[47m This is a system app,\ninstalling it is potentially\nmore risky than regular DSiWare.\n\x1B[33m";
-			const char areYouSure[] = "Are you sure you want to install\n";
+			const char systemData[] = "\x1B[41mWARNING:\x1B[47m This is a data title,\ninstalling it is extremely\nrisky. You will have a very\n\x1B[31mhigh chance of bricking!\n\x1B[33m";
+			const char areYouSure[] = "Are you sure you want to install?\n";
 			clearScreen(&topScreen); // Top screen breaks after this for some reason.
 			printTadInfo(tadPath);
 			clearScreen(&bottomScreen);
 			char* msg = (char*)malloc(strlen(system) + strlen(areYouSure) + strlen(fpath) + 2);
-			if (sdnandMode || h->tid_high == 0x00030004)
-				sprintf(msg, "%s%s?\n", areYouSure, fpath);
-			else
-				sprintf(msg, "%s%s%s?\n", system, areYouSure, fpath);
+			if (sdnandMode || h->tid_high == 0x00030004) {
+				sprintf(msg, "%s\n", areYouSure);
+			} else if (dataTitle == TRUE) {
+				sprintf(msg, "%s%s\n", systemData, areYouSure);
+			} else {
+				sprintf(msg, "%s%s\n", system, areYouSure);
+			}
 
 			bool choice = choiceBox(msg);
 			free(msg);
@@ -518,7 +526,7 @@ bool install(char* tadPath, bool systemTitle)
 		}
 		else if(!sdnandMode && !unlaunchPatches && access(tmdPath, F_OK) != 0)
 		{
-			if (choicePrint("TMD not found, game cannot be\nplayed without Unlaunch's\nlauncher patches.\nSee wiki for how to get a TMD.\n\nInstall anyway?") == YES)
+			if (choicePrint("TMD not found, game cannot be\nplayed without Unlaunch's\nlauncher patches.\n\nInstall anyway?") == YES)
 				tmdFound = false;
 			else
 				goto error;
@@ -558,20 +566,10 @@ bool install(char* tadPath, bool systemTitle)
 		*/
 
 		//check that there's space on nand
-		/*
 		if (!_checkDsiSpace(installSize, (h->tid_high != 0x00030004)))
 		{
-			if (sdnandMode && choicePrint("Install as system title?"))
-			{
-				h->tid_high = 0x00030015;
-				fixHeader = true;
-			}
-			else
-			{
-				goto error;
-			}
+			goto error;
 		}
-		*/
 
 		//check for saves
 		char pubPath[PATH_MAX];
@@ -625,10 +623,9 @@ bool install(char* tadPath, bool systemTitle)
 		char dirPath[32];
 		mkdir(sdnandMode ? "sd:/title" : "nand:/title", 0777);
 
-		sprintf(dirPath, "%s:/title/%08x", sdnandMode ? "sd" : "nand", (unsigned int)h->tid_high);
+		sprintf(dirPath, "%s:/title/%02x%02x%02x%02x", sdnandMode ? "sd" : "nand", srlTidHigh[0], srlTidHigh[1], srlTidHigh[2], srlTidHigh[3]);
 		mkdir(dirPath, 0777);
-
-		sprintf(dirPath, "%s:/title/%08x/%08x", sdnandMode ? "sd" : "nand", (unsigned int)h->tid_high, (unsigned int)h->tid_low);
+		sprintf(dirPath, "%s:/title/%02x%02x%02x%02x/%02x%02x%02x%02x", sdnandMode ? "sd" : "nand", srlTidHigh[0], srlTidHigh[1], srlTidHigh[2], srlTidHigh[3], srlTidLow[0], srlTidLow[1], srlTidLow[2], srlTidLow[3]);
 		
 		//check if title is free
 		if (_titleIsUsed(h))
@@ -716,7 +713,7 @@ bool install(char* tadPath, bool systemTitle)
 
 				//pad out banner if it is the last part of the file
 				{
-					if (h->ndshdr.bannerOffset > (fileSize - 0x23C0))
+					if (h->ndshdr.bannerOffset > (fileSize - 0x23C0) && dataTitle == FALSE)
 					{
 						iprintf("Padding banner...");
 						swiWaitForVBlank();
@@ -833,15 +830,16 @@ bool install(char* tadPath, bool systemTitle)
 		//ticket folder /ticket/XXXXXXXX
 		if (tmdFound)
 		{
+
 			//ensure folders exist
 			char ticketPath[32];
 			siprintf(ticketPath, "%s:/ticket", sdnandMode ? "sd" : "nand");
 			mkdir(ticketPath, 0777);
-			siprintf(ticketPath, "%s/%08lx", ticketPath, h->tid_high);
+			siprintf(ticketPath, "%s/%02x%02x%02x%02x", ticketPath, srlTidHigh[0], srlTidHigh[1], srlTidHigh[2], srlTidHigh[3]);
 			mkdir(ticketPath, 0777);
 
 			//actual tik path
-			siprintf(ticketPath, "%s/%08lx.tik", ticketPath, h->tid_low);
+			siprintf(ticketPath, "%s/%02x%02x%02x%02x.tik", ticketPath, srlTidLow[0], srlTidLow[1], srlTidLow[2], srlTidLow[3]);
 
 			if (access(ticketPath, F_OK) != 0 || (choicePrint("Ticket already exists.\nKeep it? (recommended)") == NO && choicePrint("Are you sure?") == YES))
 				_createTicket(h, ticketPath);
@@ -872,6 +870,7 @@ complete:
     remove("sd:/_nds/TADDeliveryTool/tmp/temp.srl.enc");
     remove("sd:/_nds/TADDeliveryTool/tmp/temp.srl");
     rmdir("sd:/_nds/TADDeliveryTool/tmp");
+    rmdir("sd:/_nds/TADDeliveryTool");
 
 	return result;
 }

arm9/src/installmenu.c

@@ -1,5 +1,6 @@
 #include "main.h"
 #include "rom.h"
+#include "tad.h"
 #include "install.h"
 #include "menu.h"
 #include "storage.h"

arm9/src/main.c

@@ -203,7 +203,7 @@ int main(int argc, char **argv)
 		}
 		else if (!unlaunchPatches)
 		{
-			messageBox("Unlaunch's Launcher Patches are\nnot enabled. You will need these\nto boot any TADs.\n\n\x1B[46mhttps://dsi.cfw.guide/\x1B[47m");
+			messageBox("Unlaunch's Launcher Patches are\nnot enabled. You will need theseto boot some TADs.\n\n\x1B[46mhttps://dsi.cfw.guide/\x1B[47m");
 		}
 	}
 

arm9/src/tad.c

@@ -22,11 +22,9 @@
 /*
     The common keys for decrypting TADs.
 
-    DEV: Used in most TADs. Anything created with the standard maketad will be dev.
-    PROD: Used in some TADs for factory tools like PRE_IMPORT and IMPORT. Really uncommon. I only know of 24 prod TADs
-        to have ever been found, and 19 of those haven't ever been released (pleeeeeaaaaase release IMPORT soon).
-        All retail signed and can't be created with any leaked maketads.
-    DEBUGGER: Used in TwlSystemUpdater TADs. Created with maketad_updater.
+    DEV: Used for most TADs. Anything created with the standard maketad will be dev.
+    PROD: Used for some TADs in factory tools like PRE_IMPORT and IMPORT. They can be created from the NUS or manually from NAND.
+    DEBUGGER: Used for TwlSystemUpdater TADs. Created with maketad_updater, not really common to see.
     
     If for whatever reason you want to make TADs, see here:
     https://randommeaninglesscharacters.com/dsidev/man/maketad.html
@@ -71,10 +69,14 @@ typedef struct {
     uint32_t metaOffset;
 } Tad;
 unsigned char srlCompany[2];
-unsigned char srlTidLow[4];
-unsigned char srlTidHigh[4];
 unsigned char srlVerLow[1];
 unsigned char srlVerHigh[1];
+unsigned char contentHash[20];
+unsigned char srlTidLow[4];
+unsigned char srlTidHigh[4];
+uint32_t srlTrueSize;
+bool dataTitle;
+
 
 uint32_t swap_endian_u32(uint32_t x) {
     return (x >> 24) | ((x >> 8) & 0xff00) | ((x << 8) & 0xff0000) | (x << 24);
@@ -95,13 +97,13 @@ void decrypt_cbc(const unsigned char* key, const unsigned char* iv, const unsign
     aes_crypt_cbc(&ctx, AES_DECRYPT, dataSize, iv, encryptedData, decryptedData);
 }
 
-int openTad(char const* src) {
-	if (!src) return 1;
+char* openTad(char const* src) {
+	if (!src) return "ERROR";
 
     FILE *file = fopen(src, "rb");
     if (file == NULL) {
         printf("ERROR: fopen()");
-        return 1;
+        return "ERROR";
     }
 
     // idk how to create folders recursively
@@ -110,10 +112,7 @@ int openTad(char const* src) {
     mkdir("sd:/_nds/TADDeliveryTool/tmp", 0777);
 
     /*
-    Please excuse my terrible copy paste coding. I do not know C and I'm translating from other languages
-    that I don't know (python, perl). 
-
-    Anyways, the code below is determining the file offsets and sizes within the TAD.
+    The code below is determining the file offsets and sizes within the TAD.
     This is done using the 32 byte header.
 
     Example header from "KART_K04.tad"
@@ -126,7 +125,7 @@ int openTad(char const* src) {
      Hex       | Dec    | Meaning
     -----------+--------+------------
     0x00000020 | 32     | Header size
-    0x4973     | Is     | TAD type
+    0x4973     | 18803  | TAD type (always "Is" in ASCII)
     0x0000     | 0      | TAD version
     0x00000E80 | 3712   | Cert size
     0x00000000 | 0      | Crl size
@@ -145,56 +144,52 @@ int openTad(char const* src) {
     iprintf("Parsing TAD header...\n");
     Tad tad;
     tad.hdrOffset = 0;
+
+    // 18803 = "Is". This is the standard TAD type.
+    // Others exist, but they are for Wii boot2 (ib) and netcard (NULL)
+    if (swap_endian_u16(header.tadType) == 18803) {
+        //iprintf("  tadType:      'Is'\n");
+    } else {
+        iprintf("  tadType:      UNKNOWN\nERROR: unexpected TAD type\n");
+        return "ERROR";
+    }
+
     // All offsets in the TAD are aligned to 64 bytes.
+    // TODO: Make sure offset calculation and alignment is correct by comparing that to total size
     tad.certOffset = round_up(swap_endian_u32(header.hdrSize), 64);
     tad.crlOffset = round_up(tad.certOffset + swap_endian_u32(header.certSize), 64);
     tad.ticketOffset = round_up(tad.crlOffset + swap_endian_u32(header.crlSize), 64);
     tad.tmdOffset = round_up(tad.ticketOffset + swap_endian_u32(header.ticketSize), 64);
     tad.srlOffset = round_up(tad.tmdOffset + swap_endian_u32(header.tmdSize), 64);
     tad.metaOffset = round_up(tad.srlOffset + swap_endian_u32(header.srlSize), 64);
-    // TODO: Make sure offset calculation and alignment is correct by comparing that to total size
-    //iprintf("  hdrSize:      %lu\n", swap_endian_u32(header.hdrSize));
-    //iprintf("  hdrOffset:    %lu\n", tad.hdrOffset);
+    /*
+    Okay sooo this is stupid. Content size defined in header != true content size
     
-    // Commenting this block out makes the TAD decrypt improperly. Truly a programming moment.
-    // 18803 = "Is". This is the standard TAD type.
-    if (swap_endian_u16(header.tadType) == 18803) {
-        //iprintf("  tadType:      'Is'\n");
-    } else {
-        iprintf("  tadType:      UNKNOWN\nERROR: unexpected TAD type\n");
-        return 1;
-    }
+    sysmenuVersion has the header content size aligned to 64 bytes
+    The TMD content size + hash is for an unpadded content
     
-    //iprintf("  tadVersion:   %u\n", swap_endian_u16(header.tadVersion));
-    //iprintf("  certSize:     %lu\n", swap_endian_u32(header.certSize));
-    //iprintf("  certOffset:   %lu\n", tad.certOffset);
-    //iprintf("  crlSize:      %lu\n", swap_endian_u32(header.crlSize));
-    //iprintf("  crlOffset:    %lu\n", tad.crlOffset);
-    //iprintf("  ticketSize:   %lu\n", swap_endian_u32(header.ticketSize));
-    //iprintf("  ticketOffset: %lu\n", tad.ticketOffset);
-    //iprintf("  tmdSize:      %lu\n", swap_endian_u32(header.tmdSize));
-    //iprintf("  tmdOffset:    %lu\n", tad.tmdOffset);
-    //iprintf("  srlSize:      %lu\n", swap_endian_u32(header.srlSize));
-    //iprintf("  srlOffset:    %lu\n", tad.srlOffset);
-    //iprintf("  metaSize:     %lu\n", swap_endian_u32(header.metaSize));
-    //iprintf("  metaOffset:   %lu\n", tad.metaOffset);
+    As such I think that the TMD size should always be the default.
+    */
+    fseek(file, tad.tmdOffset+496, SEEK_SET);
+    fread(&srlTrueSize, 1, 4, file);
+    fread(contentHash, 1, 20, file);
 	
     fseek(file, tad.tmdOffset+396, SEEK_SET);
     fread(srlTidHigh, 1, 4, file);
     fread(srlTidLow, 1, 4, file);
+
     fclose(file);
 
     /*
     Copy the contents of the TAD to the SD card.
 
-    For installing we only need the TMD, ticket, and SRL (obviously lol).
+    For installing we only need the TMD, ticket, and SRL.
 
-    We can skip the cert since that already exists in NAND, and using the TAD's cert could introduce problems like
-    trying to sign files for dev on a prod console.
+    We can skip the cert since that already exists in NAND, and the TADs cert might not match the signing on the DSi.
     */
 
     iprintf("Copying output files...\n");
-    // Sorry for copy pasting, I'll make this a routine later
+
     iprintf("  Copying TMD...\n"); 
     copyFilePart(src, tad.tmdOffset, swap_endian_u32(header.tmdSize), "sd:/_nds/TADDeliveryTool/tmp/temp.tmd");
 
@@ -202,7 +197,7 @@ int openTad(char const* src) {
     copyFilePart(src, tad.ticketOffset, swap_endian_u32(header.ticketSize), "sd:/_nds/TADDeliveryTool/tmp/temp.tik");
     
     iprintf("  Copying SRL...\n"); 
-    copyFilePart(src, tad.srlOffset, swap_endian_u32(header.srlSize), "sd:/_nds/TADDeliveryTool/tmp/temp.srl.enc");
+    copyFilePart(src, tad.srlOffset, swap_endian_u32(srlTrueSize), "sd:/_nds/TADDeliveryTool/tmp/temp.srl.enc");
 
     /*
     Get the title key + IV from the ticket.
@@ -215,46 +210,47 @@ int openTad(char const* src) {
     fseek(ticket, 447, SEEK_SET);
     fread(title_key_enc, 1, 16, ticket);
     //iprintf("  Title key found!\n");
-    /* for (int i = 0; i < 16; i++) {iprintf("%02X", title_key_enc[i]);} */
-    iprintf("\n");
+
     //iprintf("  Finding title key IV...\n");
     unsigned char title_key_iv[16];
     fseek(ticket, 476, SEEK_SET);
     fread(title_key_iv, 1, 8, ticket);
     memset(title_key_iv + 8, 0, 8);
     //iprintf("  Title key IV found!\n");
-    /* for (int i = 0; i < 16; i++) {iprintf("%02X", title_key_iv[i]);} */
-    iprintf("\n");
+
     fclose(ticket);
 
     /*
     This is SRL decryption (AES-CBC).
     
-        Common key + title key IV to decrypt title key, title key + content IV to decrypt content
+        Common key + title key IV to decrypt title key
+        Title key + content IV to decrypt content
 
     We have to try each possible common key until we find one that works. I don't know a better way to do this
     (nothing in the TAD would specify the key needed) so we'll try keys in the order of which ones are more common:
 
-        DEV --> DEBUGGER --> PROD
-
-    We check for only zerobytes at 0x15-1B to see if the SRL is decrypted properly. (should always be zerobytes)
-    
-    https://problemkaputt.de/gbatek.htm#dscartridgeheader
-    https://gist.github.com/rvtr/f1069530129b7a57967e3fc4b30866b4#file-decrypt_tad-py-L84
+        DEV --> PROD --> DEBUGGER
     */
+
+    if (srlTidHigh[3] == 0x0f) {
+        dataTitle = TRUE;
+    } else {
+        dataTitle = FALSE;
+    }
+
     bool keyFail;
     iprintf("Trying dev common key...\n");
-    keyFail = decryptTad(devKey, title_key_iv, title_key_enc, content_iv, swap_endian_u32(header.srlSize), srlTidLow);
+    keyFail = decryptTad(devKey, title_key_iv, title_key_enc, content_iv, swap_endian_u32(srlTrueSize), srlTidLow, dataTitle, contentHash);
 
-    if (keyFail == TRUE) {
-        remove("sd:/_nds/TADDeliveryTool/tmp/temp.srl");
-        iprintf("Key fail!\n\nTrying debugger common key...\n");
-        keyFail = decryptTad(debuggerKey, title_key_iv, title_key_enc, content_iv, swap_endian_u32(header.srlSize), srlTidLow);
-    }
     if (keyFail == TRUE) {
         remove("sd:/_nds/TADDeliveryTool/tmp/temp.srl");
         iprintf("Key fail!\n\nTrying prod common key...\n");
-        keyFail = decryptTad(prodKey, title_key_iv, title_key_enc, content_iv, swap_endian_u32(header.srlSize), srlTidLow);
+        keyFail = decryptTad(prodKey, title_key_iv, title_key_enc, content_iv, swap_endian_u32(srlTrueSize), srlTidLow, dataTitle, contentHash);
+    }
+    if (keyFail == TRUE) {
+        remove("sd:/_nds/TADDeliveryTool/tmp/temp.srl");
+        iprintf("Key fail!\n\nTrying debugger common key...\n");
+        keyFail = decryptTad(debuggerKey, title_key_iv, title_key_enc, content_iv, swap_endian_u32(srlTrueSize), srlTidLow, dataTitle, contentHash);
     }
     if (keyFail == TRUE) {
         remove("sd:/_nds/TADDeliveryTool/tmp/temp.srl");
@@ -270,7 +266,9 @@ bool decryptTad(unsigned char* commonKey,
                 unsigned char* title_key_enc,
                 unsigned char* content_iv,
                 int srlSize,
-                unsigned char* srlTidLow) {
+                unsigned char* srlTidLow,
+                bool dataTitle,
+                unsigned char* contentHash) {
     unsigned char title_key_dec[16];
     unsigned char title_key_iv_bak[16];
     unsigned char content_iv_bak[16];
@@ -290,20 +288,62 @@ bool decryptTad(unsigned char* commonKey,
     decrypt_cbc(commonKey, title_key_iv, title_key_enc, 16, 16, title_key_dec);
     int i=0;
     bool keyFail = FALSE;
-    while (i < srlSize && keyFail == FALSE) {
-        fread(srl_buffer_enc, 1, 16, srlFile_enc);
-        decrypt_cbc(title_key_dec, content_iv, srl_buffer_enc, 16, 16, srl_buffer_dec);
-        fwrite(srl_buffer_dec, 1, 16, srlFile_dec);
-        printProgressBar( ((float)i / (float)srlSize) );
-        if (i == 560) {
-            if (srl_buffer_dec[3] != srlTidLow[0] ||
-                srl_buffer_dec[2] != srlTidLow[1] ||
-                srl_buffer_dec[1] != srlTidLow[2] ||
-                srl_buffer_dec[0] != srlTidLow[3] ) {
+
+    /*
+    Why have two methods of decrypting for data and normal titles?
+    
+    Normal titles can be massive (16mb)! Decrpyting and calculating SHA1 multiple times to test keys
+    is painfully slow. We can quickly test the SRL header for the TID to make sure the key works.
+    
+    Data titles can't be tested the same way. Since they're just data, they don't have a header to read.
+    Luckily they tend to be small (10-300kb) so completely decrypting and checking a SHA1 hash is fast.
+    */
+
+    if (dataTitle == TRUE) {
+        // Copied SHA1 stuff from here.
+        // https://github.com/DS-Homebrew/SafeNANDManager/blob/master/arm9/source/arm9.c#L96-L152
+        swiSHA1context_t ctx;
+        ctx.sha_block=0;
+        u8 sha1[20]={0};
+        swiSHA1Init(&ctx);
+
+        while (i < srlSize) {
+            fread(srl_buffer_enc, 1, 16, srlFile_enc);
+            decrypt_cbc(title_key_dec, content_iv, srl_buffer_enc, 16, 16, srl_buffer_dec);
+            fwrite(srl_buffer_dec, 1, 16, srlFile_dec);
+            printProgressBar( ((float)i / (float)srlSize) );
+            swiSHA1Update(&ctx, srl_buffer_dec, 16);
+            i=i+16;
+
+        }
+        swiSHA1Final(sha1, &ctx);
+
+        // Compare SHA1 hash of file to TMD
+        for (int i = 0; i < 20; i++) {
+            if (contentHash[i] != sha1[i]) {
                 keyFail = TRUE;
             }
         }
-        i=i+16;
+        iprintf("\n");
+
+    } else {
+        while (i < srlSize && keyFail == FALSE) {
+            fread(srl_buffer_enc, 1, 16, srlFile_enc);
+            decrypt_cbc(title_key_dec, content_iv, srl_buffer_enc, 16, 16, srl_buffer_dec);
+            fwrite(srl_buffer_dec, 1, 16, srlFile_dec);
+            printProgressBar( ((float)i / (float)srlSize) );
+    	   // Executable SRLs will always have a reverse order TID low at 0x230. 
+    	   // Use this to check if the current common key works.
+            if (i == 560) {
+                if (srl_buffer_dec[3] != srlTidLow[0] ||
+                    srl_buffer_dec[2] != srlTidLow[1] ||
+                    srl_buffer_dec[1] != srlTidLow[2] ||
+                    srl_buffer_dec[0] != srlTidLow[3] ) {
+                    keyFail = TRUE;
+                }
+            }
+            i=i+16;
+        }
     }
     fclose(srlFile_dec);
     fclose(srlFile_enc);
@@ -354,9 +394,9 @@ void printTadInfo(char const* fpath)
     for (int i = 0; i < 4; i++) {printf("%c", srlTidLow[i]);}
     iprintf("\x1B[47m");    //white
 
-    iprintf("\nGame Version:\n  \x1B[42m%d.%d\x1B[47m (NUS: \x1B[42mv%d\x1B[47m)\n", (int)srlVerHigh[0] * 256, (int)srlVerLow[0], ((int)srlVerHigh[0] * 256) + (int)srlVerLow[0]);
+    iprintf("\nGame Version:\n  \x1B[42m%d.%d\x1B[47m (NUS: \x1B[42mv%d\x1B[47m)\n", (int)srlVerHigh[0], (int)srlVerLow[0], ((int)srlVerHigh[0] * 256) + (int)srlVerLow[0]);
 
-    iprintf("Company Code:\n  \x1B[42m%c%c\x1B[47m(\x1B[42m%02x%02x\x1B[47m)\n", srlCompany[0], srlCompany[1], srlCompany[0], srlCompany[1]);
+    iprintf("Company Code:\n  \x1B[42m%c%c\x1B[47m (\x1B[42m%02x%02x\x1B[47m)\n", srlCompany[0], srlCompany[1], srlCompany[0], srlCompany[1]);
     
     // Print program type based on TID high?
     iprintf("Title ID: \n  ");

arm9/src/tad.h

@@ -4,12 +4,18 @@
 #include <nds/ndstypes.h>
 #include <nds/memory.h>
 
-int openTad(char const* src);
+char* openTad(char const* src);
 bool decryptTad(unsigned char* commonKey,
                 unsigned char* title_key_iv,
                 unsigned char* title_key_enc,
                 unsigned char* content_iv,
                 int srlSize,
-                unsigned char* srlTidLow);
+                unsigned char* srlTidLow,
+                bool dataTitle,
+                unsigned char* contentHash);
+void printTadInfo(char const* fpath);
+extern bool dataTitle;
+extern unsigned char srlTidLow[4];
+extern unsigned char srlTidHigh[4];
 
 #endif