I've found that Claude Code works well at reversing java applications. Even if it is fully obfuscated claude can restore sensible names for everything and understand how it all works and answer questions about what it is doing.
+1. While vibe-coding (natural language to code) is not such a great idea, we can always check the source, so vibe-reverse-engineering (code to natural language) may actually be quite useful.
Mark gave me the ROM image, I tried using more conventional decompiling methods but the chips were exotic enough that I didn't get good results and as a last resort, I put it into Claude raw. Claude was actually able to parse the binary and sort of decompile it. It was able to tell me what the ports did and what the interfacing protocols were.
It then started making stuff up, clearly trying to impress me, but after a few rounds of reprimanding it and saying how making stuff up wasn't helpful, Claude stuck to facts.