This patcher allows the game to load IoStore or non-IoStore pak files, supporting audio, texture, mesh, and material modding. 

I released an updated patch ( https://www.nexusmods.com/mortalkombat/mods/7?tab=files&file_id=175 ) which should work for any previous or future releases.  I verified that it works for the Nov. 9 Omni-Man release. 

Update to the latest version of the game and then download the latest version of the patch.  Unzip patch_proj.exe and stick it in MK12\Binaries\Win64 and then double-click patch_proj.exe ONCE, which will patch MK12.exe

If you run into any issues, do verify file integrity in Steam and then double-click patch_proj.exe ONCE, which will patch MK12.exe

Also set -fileopenlog in Steam's launch options

To install:
1) Make sure you have the original MK12.exe, especially if you installed my previous patch:  Right-click Mortal Kombat 1 in your Steam library, and in the "Installed Files" tab, verify the integrity of the game files.
2) Unzip patch_proj.exe and stick it in MK12\Binaries\Win64 and then double-click patch_proj.exe ONCE, which will patch MK12.exe
3) I recommend backing up your MK12.exe, although my program should also make a backup.
4) Double-click patch_proj.exe.  You should see a orig_mk12.exe, which is a backup of the original exe, and a new MK12.exe which is patched.

You also must set -fileopenlog in Steam's launch options:  right-click Mortal Kombat 1 in your Steam library, and in the "General" tab, scroll all the way down to launch options and type in "-fileopenlog", as shown in the image.

Only legacy pak mods (e.g., audio mods) should be in ~mods.  IoStore mods should be in LogicMods (e.g., in  steamapps\common\Mortal Kombat 1\MK12\Content\Paks\LogicMods ), not in ~mods.

Disclaimer:  Highly recommend keeping both the original EXE (which the patch saves for you as orig_mk12.exe), as well as the patched EXE, and only using the patched EXE and mods for customizing your local single-player experience, while using the original EXE when playing online.  We are not employed by the devs and are not responsible if anyone who uses this gets banned.

Sample audio mod
Sample texture mod
Sample material mod
Sample mesh mod

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High-level MK1 (aka MK12) Modding Tutorial for Meshes and Textures

Author: peek6

NOTE:  this is a high-level description meant for modders with at least some prior experience modding UE games.  Modding MK is slightly more
complicated.  This guide focuses mostly on the differences between MK modding and modding other MK games.  For any questions, post to the MKsecrets and ModdingHaven discord servers on the threads here and here.  Join the Discord servers first or the links to the threads won't work.

 - Patch the game using  https://www.nexusmods.com/mortalkombat/mods/7 to enable mods

 - Extract assets using Umodel from: https://drive.google.com/file/d/1CnnVSOPQ_F3UtebOkBXLGd0V5w2XNFIY/view
     - Set game to Mortal Kombat
     - Disable morph targets
     - AES key = 0x6FAABA4F4EF8A6AC188A517ACEF38F1422484E3B1F3F4CF3DACB27A6CBCCD076
     - Export assets as PSK for models, TGA for textures.  I also recommend saving the original raw uassets.

 - Import the PSK into Blender using https://github.com/matyalatte/blender3d_import_psk_psa/releases
 
 - Modify the mesh as desired and export to FBX using the same plugin
 
 - You can also modify textures (which you exported as TGA in Umodel) using PhotoShop
 
 -  Link your Epic and github accounts ( https://www.epicgames.com/help/en-US/epic-accounts-c5719348850459/connected-accounts-c5719351300507/how-do-i-link-my-console-account-to-my-epic-games-account-using-the-web-a5720357639451 ) and then grab kboy's custom MK1 UE build from https://github.com/kboykboy2/UnrealEngine/releases .
 
 - Create a project called MK12, set up folder structure so it is exactly identical to what you see in Umodel, and import your modded FBX meshes
and TGA textures.
 
 - In UE settings, turn on IoStore, enable chunks, and enable assigning chunks, as described in https://modding.wiki/en/hogwartslegacy/developers/getting-started (but you need to use kboy's custom UE instead of the standard Epic UE 4.27)
 
 - Point your mesh to the exact same MIs, skeletons, physics assets, and animation blueprints as you see when you open the original raw uasset in
a hex editor.  It must be exactly the same name and path.
 
 - Put only your meshes and textures into a chunk larger than 23 (do not put any MIs, skeletons, physics, or anim blueprints into the chunk) and
package the project.

 - Add _P to the end of all your packaged chunk's filenames and stick them in steamapps\common\Mortal Kombat 1\MK12\Content\Paks\LogicMods (not in ~mods , which is for audio mods only)