Okay so now I can upload text files but no binary files:
var files = e.target.files;
var data = new FormData();
data.append('upload', files[0]);
$.ajax({
url: 'upload',
type: 'POST',
data: data,
conentType: 'multipart/form-data',
processData: false
});
[B3C49FB1:AFCF17B1 dbg] Exception while handling request POST /upload: Invalid UTF sequence: a6 - Invalid UTF-8 sequence (at index 1)