The patch you'll require to play the most recent version of the GoldenEye: X mod (4a). Other details on how to patch the ROM are included.
Inside this zip, you will find four files: the first and second are both XDelta patches, which can be patched to your unmodified Perfect Dark v1.1 NTSC ROM. Only use the console version if you plan to play on a backup device, or are using an emulator that can properly render the clouds. The third is a readme.txt, which includes various information about the current version of the mod. Updates, special notes, and many of the glitches are listed. Lastly, is a text file that tells the difference between the regular and console versions.
If you don't know how to apply an XDelta patch, you'll probably want to download the GoldenEditor / Perfect Editor combo program from the GoldenEye Vault. Here is a direct link to the download page...
With the program open, go to "Tools". From the selection menu, highlight "XDelta Patching". Choose "Apply PD XDelta Patch" from the list. First you will need to find and select your PD v1.1 NTSC ROM. Afterward, select the XDelta patch. You will then be asked to save your new ROM. After a few moments, the process should complete. Simply load it up in the emulator (or backup device) of your choice, and enjoy!