Now this is a certified hashbrown moment

Okie dokie ! Well, now that I'm awake... Here we go !


0 - Preparation) Make sure the game is on GameMaker: Studio 1. This can be done by opening the .exe as an archive with 7zip, and checking if there's a data.win file. If there is, cool ! It might work !
Download this thing, as hinted at in many of m1s3ry's ports... https://github.com/krzys-h/UndertaleModTool/releases
You'll also need xdelta3.exe, which is a patching thing. Also, while you're at it, grab this https://www.romhacking.net/utilities/704/
UTMT allows you to create the modification itself, Delta Patcher allows you to make a single "difference file" thingy that can be used to patch the data.win for Vita use, and xdelta3.exe actually patches the data.win WITH the patch file. So, it's not y'arr h'arr fideldy dee, **you'll need the original game files if you are the end user.**
oh right and GayMaker is required too

Got all of that ? Are we good ? lettuce move on

1 - Creating the Vita version) So first of all, if you wanna make a Vita version of a GMS:1 game... You need some sort of "dummy" VPK, as i like to call it. Basically, you can make this whatever you want, but you need to have at least one room, maybe a graphic telling you that you didn't install the game, something like that. The reason this is needed, is because of how we get the game onto the Vita in the first place. The VPK holds no game code whatsoever.
If you don't have it set up already, get GayMaker. I won't provide any links. But it's kind of essential in this process, you gotta get the "dummy project" on the Vita somehow :L
The rest for this step is self-explanatory, make all the fancy LiveArea graphics you want !

2 - Checking stuffz) SO ! This part is pretty easy. All you gotta do, is export the dummy project as an .exe file. Why ? Well, you need to check your own data.win ! Open up Undertale Mod Tool (which i will now refer to as "UTMT"), thwoomp your own data.win into there, and check "general info"
There's a thing in there, "Bytecode Version"... Mine was 16. So, that's pretty important.

3 - Patching the game) Here comes the fun part ! Or, one of them. Open the data.win of the game you wanna port in UTMT, then check the bytecode version. Let's say it's 14. ARE YOU READY FOR THE MOST JANK SOLUTION FOR THIS PROBLEM ?
On the top bar, go to Scripts --> Run Technical Script --> 14_to_16.csx. Baddabing baddaboom,there's probably more to do that's very specific since each game is different, but like. Now, save the new data.win SEPARATELY. Name it whatever you want

4 - Patching the game 2: Electric Boogaloo, Optional edition) This is only for if you're releasing the thing on Github.
Now you need to actually create the patch for the data.win. Gonna speedrun the explanation of this one, ya ready ?

Oprn up Delta Patcher.exe, and click the two arrows with a light blue background icon thing on the bottom. This will put into "create a patch you dip" mode. Put the original data.win in "original file", then the new one you made in step 3 in "modified file", then click the save icon on "xdelta patch". This will make you choose where you wanna put it !
Click "create patch", and BOOM. You did it ! Almost.

5 - Put it on Vita) NOW, with the newly created data.win that is patched and stuff... Rename it to game.win. Install the dummy VPK. AND NOW !!! Go to the "app" folder from the root of ux0 (i hope that is correct terminology), then choose whichever folder you made your dummy VPK, go to games folder, and schlap game.win right up in there. Overwrite when prompted.
Oh yeah, and before I forget ! If the original game exe had .ogg files in it, or some other stuff... Put those also in the same folder as game.win. On the Vita. ...Yeah. (You don't need to modify those, by the way)

6 - Congratulations) YOU'RE WINNER


I really hope I did a good job explaining this .-.