This program performs patches on the game's memory; it will NOT persist after a restart. If you need to restart your game for any reason, you can simply run the program again and re-patch the game. Additionally, there is a non-zero chance that it can cause the game to crash. Even if I believe the program is stable, you should only run it AFTER saving your data.
Also, bare in mind that icons will still appear as locked. If the patch was successful, you should be able to select any icons you wish regardless of whether or not you have them unlocked.
Lastly, it is almost (if not completely) impossible for me to prove that the compiled executable is safe to run.
Instead, consider compiling it from the source code. All you need is Visual Studio w/ Desktop development with C++ installed to do so.
My custom icon hack for Geometry Dash 2.2 on Windows systems (literally any version Windows 7 and above). You do not need administrator privileges for this to work.
This will be updated as soon as possible each time Geometry Dash is updated as a temporary replacement for Mega Hack and Geode's icon hacks.
If you encounter any issues, please submit an issue in the Issues tab and I will take a look. If you have an improvement to propose, consider creating a pull request!