I've recently been undertaking a little RE project where I needed to patch the executable. For small modifications, I know enough x86 to patch in an jump, nop, infinite loop, etc, so a hex editor is good enough. But what about larger ones?
I used to use OllyDbg for this, there were great tools in it, you could go to any line, press space and just start assembling, instructions you replaced would be padded with NOPs automatically and there were even nice plugins to find code caves.
Unfortunately, OllyDbg seems barely updated these days and fails to load any application on 64 bit Windows 8.1, so I've switched to Hiew. Hiew isn't bad, but the interface is well, more than a little dated and fairly cumbersome to use compared to Olly's.
I'm wondering if anyone knows any more modern tools that can perform this same sort of function.