This editor works for all Maddens on 360/PS3. I'm guessing that you didn't hex edit the roster after editing. The Editor and Horizon can be found in the first post of Xanathal's editor thread. Just google HxD and the program should be in the first search result. I've listed the steps below to editing and transferring rosters. I recommend doing one small change like giving Tom Brady 99 speed the first time you do an edit to make sure everything works correctly. After you have successfully done it the first time, edit as much as you like.
What you need:
Xbox 360 formatted flash drive
Madden Roster Editor – To edit the players
Horizon – To transfer the roster to your flash drive
HxD – To Hex edit the roster so it will work after editing
The Steps:
1. Create 2 folders on your Desktop and label them edit and default.
2. Insert your flash drive into the USB port and open Horizon.
3. In Horizon, Go to Device Explorer, then games, choose the correct game (M17 in this case) and then select the roster save file you wish to edit. Double click on the file and go to Contents. Now right click on the file and choose Extract and put a copy of the roster in both the edit and default folders that you created. Exit Horizon for now but leave Horizon open.
4. Open the Madden Editor (Madden 12 Roster Reader is the official name of Xanathal’s editor) and select File, Open Roster and choose the roster in your edit folder. Make some edits. After you have finished your edits, select File and choose Save Roster. Close the Madden Editor.
5. Open Hxd and select File and choose Open. Select the roster file in your default and edit folders. Copy the entire 2nd line of numbers in your default roster and paste it over the 2nd line of numbers in your edit roster. Now select File and Save the changes you made to your edit roster. Close HxD.
6. Go back to Horizon and choose the roster file that you edited from your flash drive and double click on the file and go to Contents. (If you left everything open on Horizon, you are already in there.) Right click on the roster and choose Replace and select the roster in your edit folder. A pop up window should appear saying that the file has been replaced successfully. Now press the Save, Rehash and Resign red tab directly above the roster file. Another pop up window should say that the file was Resigned correctly. You are now done.
Edit: I included a M15 classic teams roster that I made ported to M17. It has virtually every big name player from the past 30 years. You can open this roster and export the players you want to a different M17 roster if you wish. Gamefaces and audio were added to everyone that I could. All players have a real portrait or a black silhouette and correct jersey number. The player overalls will be lower than what is shown in M17 because the player overalls are calculated differently for M17 than other Madden's. I would use the editor and set all players overall at 12 and then export them so that you will know who to edit in game to give them their true M17 overall.
The maximum number of players that can be on a roster is 2971. Maximum number of players on a team is 75. Don't change a players team in the editor. Exceeding any of these things can cause glitches. If you delete a default roster player (the default roster is the roster that is used if you don't have a storage device when you start the game) they will still appear in CFM. Right click on the player and choose Replace then select the player you wish to replace them with if you don't want that player reappearing. You must Replace players instead of deleting them if you want fantasy draft to continue to work. I recommend importing players to FA and then signing them in game. I also usually do edits to ratings in game because this editor was made for M12 and won't calculate the overall correctly for newer Madden's. If for any reason you have an invisible player, release them to FA and sign them in game to fix it. Good luck and happy editing.