Required programs

GD-Rom Explorer

GDI Builder

SA1 .gdi file

1. Open GD-Rom Explorer
2. In the top left of the window, go to File - Open. And Open your SA1 .gdi file
3. Create a new folder to extract the SA1 Data into
4. On the left side of the window you will see a list of different things. Right click "SONIC_ADV" with the ISO icon to the left of it
5. Click on "Extract content of \ to..."
6. Extract the content into the folder you just made
7. Right click "IP.BIN" which is also on the left side
8. Click on the plus sign right next to "Single Density". Right click and extract "Track 02" into the same folder
9. Extract that in the folder you put the SA contents into
10. Open the folder you extracted the content into and go into the "SONIC_ADV" folder
11. Take any ADX files you want to swap and drag them into the folder
12. Once you finish swapping all the ADX's you want. Open GDI Builder
13. Click on the browse button next to Data files and set the path to where the SA content is (Not the SONIC_ADV folder but just outside of it)
14. Click the browse button next to IP.BIN and find the IP.BIN file you extracted earlier
15. Click the Add button just under where you put the IP.BIN and find the Track 02 file
16. For the Output directory, make a new folder for the modded .gdi to be placed
17. Make sure to put a copy of your SA .gdi in the new folder and rename it "disc.gdi"
18. Now just click "Create GD-ROM"