2021E Local Host Patching Guide

This guide is only how to patch the Roblox 2021E client to run on a local host. This guide is not for any other purpose, I do not recommend hosting this as a revival. This is a fixed version of jetrays guide, with modified web server, no sketchy DLLs, and way better formatting. All credit originally goes to him.

FILTERING IS DISABLED, AND SIGNING IS DISABLED! THIS IS NOT SECURE!

Requirements

• x32dbg
• HxD
• Roblox 2021E
• RCCService
• Webserver
• 2021E Content
• Visual C++ Runtime

If you cannot access the links, or if they are taken down please use the downloads in the archive directory.
I also do recommend using the webserver from this repository, it already contains the CoreGuis, and a couple of QoL fixes.

Recommended folder setup:

Patching Client

1. Open AppSettings.xml in the 2021E client folder and replace the code with the following:

<?xml version="1.0" encoding="UTF-8"?>
<Settings>
	<ContentFolder>content</ContentFolder>
	<BaseUrl>http://localhost/.127.0.0.1/</BaseUrl>
</Settings>

2. Open x32dbg, then drag the client into the window.

   • Up top, click on Smybols then in the window look for RobloxPlayerBeta.exe and double click it.
   • Up top, there should be a solid right arrow. Click on it twice, this is to get around VMProtect.

3. Right click anywhere on the code and click Search for > All Modules > String references...

   • Wait for the module search to complete, in the search bar near the bottom, type trust check and wait.
   • Double click it, or right click on the first result and click Follow in Disassembler.
   • Scroll up a little bit and you should see a jne or je instruction, right click and select assemble it or press space, then change it to jmp.
   • Repeat this step for the second result.

4. After that return to the references tab up top. Search --rbxsig4 and then double click it, or right click and click Follow in Disassembler.

   • Scroll up until you see a push ebp instruction underneath a bunch of int3 instructions.
   • Right click on the push ebp instruction and click Assemble or press space, then change the whole instruction to ret.
   
   
   - Example of what you should see:
   

   

5. Click on File > Patch File... and save it as Patched.exe.

   • Close x32dbg, then delete, rename, or move the old RobloxPlayerBeta.exe. After that, rename Patched.exe to RobloxPlayerBeta.exe.

6. Inside of the client folder create a new folder called ClientSettings and inside of that create a new file called ClientAppSettings.json and download this file and move it into the folder.

7. Extract the Content.7z and then copy all of the files (NOT MOVE) into the client directory.

   • After that create a batch file in the client directory with the following code:

   start RobloxPlayerBeta.exe -a "http://localhost/Login/Negotiate.ashx" -j "http://localhost/game/placelauncher.ashx" -t "1"

   • When you are done, it should look like the following:
     

Done! You have successfully patched the client.

Patching RCCService

1. Run 0.463.24788Bootstrapper.exe as an administrator and let it install.

   • After it is done, open the Roblox folder in the Program Files (x86) directory. In there should be a folder called RCC- followed by a bunch of random letters and numbers.
   • Open that folder and copy the contents and move them into the RCCService folder inside of your main 2021E folder.

2. Open RCCService.exe in HxD by dragging it into the window.

   • Press Ctrl + F and search for 00 68 74 74 70 73 00.
   • Replace it with 00 68 74 74 70 00 00.
   • Save the file and close HxD.

3. Perform the same trust check patching as you did with the client, but with RCCService.exe instead in x32dbg.

   • After that, you need to patch Non-trusted BaseURL used. HttpRbxApiService is only for Roblox API calls, search that string and patch the jne or je instruction to jmp like you did with the client.
   • Patch the file like you did with the client, then delete, rename, or move the old RCCService.exe and rename Patched.exe to RCCService.exe.

4. Go back to the Contents directory and copy all of the files (NOT MOVE) into the RCCService folder.

   • After that create a batch file in the RCCService directory with the following code:

   RCCService.exe -Console -verbose -placeid:1818 -localtest "gameserver.json" -settingsfile "DevSettingsFile.json" -port 64989

5. You must place these two files inside of the RCCService folder:

   • DevSettingsFile.json
   • gameserver.json

Done! You have successfully patched RCCService.

Setting up the Webserver

1. Extract the Webserver.7z and move it to your main 2021E folder.
   • Inside the Webserver folder, run uwamp.exe, and click allow twice if prompted by Windows Firewall.
   • If apache does not start make sure you have the Visual C++ Runtime installed.
2. Downloads the CoreGuis from the /coreguis/ directory in this repository, or download the compressed CoreGuis.zip file.
   • Once downloaded/extracted go into the www folder, and open the directory .test and then asset.
   • Copy all coregui files into that directory, there is no need to change the asset ids, or scripts.

Done! You have successfully set up the webserver.

Playing

you must run these in order!

1. Run UwAmp.exe in the Webserver folder. (If not already running, run UwAmpUAC if you run into issues)
2. Run RCCService.bat in the RCCService folder.
3. Run Client.bat in the client folder.

• If you would like to configure the username, avatar, etc. Its all in the webserver folder in the www directory. Or you could just use the launcher scripts in the web server, if you know how to use them, I may document them later if I feel like it.

• If you would like to test other games, inside of the www directory open the .127.0.0.1 folder, and inside of assets upload a .rbxl or .rbxlx file (make sure to remove the .rbxl/.rbxlx extension from the file name) and rename it to an id.

  • In order to actually play it modify gameserver.json in RCCService, change the id inside of the PlaceFetchUrl to the id of the place asset.
  • NOTE: I believe roblox did a change to their binary and xml formats on some channels (not live or any main ones, I am on an experimental channel), as of 3/14/24 to 3/16/24 the new binary format would not work with 2021E. This has since been fixed and you can use new place files. Please watch out for any of these changes in the future and make archives of your games that you want to play on it in the older format.

  Example:

  "PlaceFetchUrl":"http://localhost/.127.0.0.1/asset/?id=69420",

  - "PlaceFetchUrl":".../asset/?id=2753915549"
  + "PlaceFetchUrl":".../asset/?id=69420"

• If you would like to get character appearances/avatars to load, just setup a simple startercharacter in starterplayer. I won't explain how todo this cause it is super simple and if you cant figure it out you shouldn't even be following this guide. There is also the option of trying to fix it in the webserver.