UndertaleNoBorder=Fullscreen v2

Must use the NA (PCSE01116) or EU (PCSB01157) version of Undertale
Must have repatch
Using VitaShell navigate to ux0:patch and find the PCSE01116 directory for NA or PCSB01157 directory for EU, press triangle and choose open decrypted
Navigate to ux0:patch/PCSE01116/games for NA or ux0:patch/PCSB01157/games for EU and copy the data.win file to ux0 (or some other easy accessed location)
Patch the data.win with the provided xdelta patch for your region using an app such as xdelta gui
NAgame.win.xdelta for North America, EUgame.win.xdelta for Europe
Copy the patched data.win to ux0:/rePatch/PCSE01116/games for NA or ux0:/rePatch/PCSB01157/games for EU (create the directory if it doesn't exist)
Set border to none to see that it behaves like the pc version and takes up all the height