File doesn't work and has no takes no storage

[steaky45]

I've recently been wanting to ay pokemon dx a rom hack of pokemon x and everytime I input the patch file, the rom file and set output location and then press the save bottom it loads amd patches for a bit and my phone shows a message for low storage space but when it finishes loading it says error:unknown error but the patched file shows in my emulator citra but I can't open it.
Also after the storage space message appears once it has the patching/loading finishes the system ui stops responding and the low storage space message goes away with patched file shows to take up 0B on my phone every time I hit save.
Is they a fix for this or have I done something worng

[yum13241]

UniPatcher bug with some xdelta files, as real XDelta3 uses it fine.