Here's a quick method I use to edit binary files on the vim editor. Suppose that the binary file name that we need to edit is called hello. Let's open it using the xxd hex viewer utility and pipe it to the vim editor as follows using the terminal. This produces the hex view of the binary file on the vim editor.
xxd hello | vim -
%!xxd -r > hello-new
Now, you can safely quit the vim editor with q! on the command mode as you would always quit it. :) Cheers!