OK, so I made a bootable #Linux USB that I - turns out - don't apparently need after all.
Big mistake.
Now that the USB stick has a bootable non-FAT32 partition, #Windows refuses to touch it.
Windows disk partition editor is weird and dumb, and you can't just, you know, delete a thing like that. *right click on partition* WTF why is everything grayed out. Why is the user interface so cryptic.
Let's see if tomorrow I'm arsed enough to boot up my raspberrypi and just do a quick fdisk