If you're editing files like, say EDID binaries, you may want a handy hex/binary editor that can handle very large files. I like HXD - its very fast and light, and doesn't have any issue editing big files or zipping around to different offsets. It's really a hacker dream!
Its pretty straight-forward, open a file and edit it. You can edit files that are open or will be opened which is great for live-hex-editing