These zip archives contain, as of 03/31/2013, roughly 99% of the files needed to update a completely fresh NA PC installation of "Final Fantasy XI", covering every patch from late 2003 up until now. This DOES NOT include the game itself. It has been tested on two other fresh installations, and successfully updated both of them without a hitch. All of the files are in their pristine, freshly downloaded forms (still labeled as .tmp2 files), so PlayOnline will recognize them all and install them for you, letting you watch as it works.
Beyond letting PlayOnline do the actual installing, if you're wondering why these patch contents were left as .tmp2 files, it's for safety reasons, too; improper .tmp2 decompressions can be quickly reversed (while overwriting a bunch of simply-named DATs with completely incompatible yet like-named DATs cannot be). You'll only have to search the folders for misplaced .tmp2 files, delete them, and do it again. Ideally, though, you'll unzip this correctly the first time!
Instead of updating through PlayOnline, you can grab this torrent, and install everything yourself. Unless no one is seeding (and even then), it should be significantly faster. If you have the HDD space, you can also keep these archives handy in case you or a friend ever need to reinstall in the future. Continuing to seed them would be great, too.
If you're fairly experienced with modding FFXI, or are comfortable with decompressing files, you won't need detailed instructions; simply unzip this into the "\PlayOnline\SquareEnix" directory with folders intact, start PlayOnline, and let it do its thing. It will download a tiny handful of small files, then install absolutely everything, and you'll be ready to play.
Those of you who would like a little more help can follow this guide, which has additional steps to help ensure no terrible mistakes are made:
1. Using the decompression program of your choice (e.g., WinZip), open the first zip file (FFXIFullPatch-20130331.zip).
* Before you start, ensure that you have everything. You'll need the ZIP archive, and its parts: z01, z02, z03, z04, z05, and z06.
2. Click on the FINAL FANTASY XI folder to highlight it, then choose to extract the contents. Make sure your archiving program will keep the sub-directories/folders intact.
3. Extract everything to an empty folder on your HDD (e.g., C:\Temp). The folder itself doesn't matter, and you can create one if necessary, but to avoid confusion, you want one that's completely empty. Afterward, close the zip file.
3a. Now, repeat steps 1-3 for the subsequent archives (if any are present), following chronological order. If they ask you to overwrite any files while you're doing this, say "Yes"/"OK".
4. Open two Windows Explorer (File Manager) windows. On the first one (which we'll call the "Patch Window"), navigate to the folder you just unzipped the archive's contents to (e.g., C:\Temp).
5. You should see a folder titled "FINAL FANTASY XI". Open it to make sure all of the sub-directories (ROM, ROM2, ROM3, etc.) unzipped properly.
5a. If there are no sub-directories, and all you see is a bunch of .tmp2 files sitting together, you did not decompress the archive with folders intact, and may want to read your archiving program's Help File (or Google about it) to figure out how. Once you know, delete the loose contents in the folder (to make it empty again), then start over from step 1.
5b. If all the sub-directories are there, you've unzipped it correctly, and can proceed to the next step.
6. Minimize the Patch Window, and open the second, formerly unused Explorer window (which we'll call the "FFXI Window"). Now, navigate to your PlayOnline\SquareEnix directory. By default, it's located at: "C:\Program Files\PlayOnline\SquareEnix".
6a. If it's not there, your Windows installation may be on a different drive (e.g., D:\), or you may have picked a different directory while installing the program. Alternatively, you may be on a 64-bit OS, and in that case, it will be in "\Program Files (x86)\PlayOnline\SquareEnix".
7. Now, arrange both the Patch Window and the FFXI Windows so they're side-by-side. You've reached the moment of truth: drag and drop the Patch Window's unzipped "FINAL FANTASY XI" folder to the open \SquareEnix\ directory in the FFXI Window. You should be prompted about merging folders and files, and you want to say "Yes"/"OK". (There's a picture below which visually illustrates this, too.)
8. The two FINAL FANTASY XI folders should become one. At this point, you can start PlayOnline and sign in normally. A file check will run, a couple of small files will download, and everything will install. If done correctly, it will take a matter of minutes rather than hours and hours of downloading.
EU/JP NOTE: According to a BlueGartr poster's account, if you try to use this archive to update a EU/JP installation, around 1,200 files will be considered corrupt during a File Check, and will have to be re-downloaded and replaced. Therefore, for EU/JP users, this may still save you some time, or it could cause an even bigger headache. Whether to use it or not regardless is up to you.
That about does it. Since we've reached the end, here's a smarmy disclaimer: whatever you do to your installation of FINAL FANTASY XI (or your computer, for that matter) is your responsibility. If this somehow hoses your FFXI installation (which should not be possible, per the note at the top covering why .tmp2 files were used), reinstall and start over. If you figure out a way to destroy your entire computer with this archive, that would not only be impressive, but would also be your fault and your responsibility to fix.
I genuinely hope this helps people avoid downloading everything from the PlayOnline servers whenever they've completed a fresh installation. Enjoy.