For example, with the Challenger explosion, it's O-rings vs. the culture and organizational deficits that led to: the O-rings, failure to revise the seal structure despite evidence of problems on prior launches, and the final decision to launch Challenger.
All of that is arguably the most interesting part.
Firmware mods would be more doable, assuming it isn't locked down.
http://www.brendangregg.com/blog/2021-05-09/poor-disk-perfor...
People also make their own toy CPU's for fun with quite some regularity - using FPGA's and other tools, the same as the pros.
And people decap and reverse engineer new CPU's like Apples M1.
* install Linux to your hard drive firmware
https://spritesmods.com/?art=hddhack
The difference is, these hacks we've mentioned are software and solid-state electronics hack. On the other hand, doing a hard drive failure analysis in the mechanical realm is totally a different challenge, a hard drive is hard.
It's a bad sign when tech complexity gets out of the expertise of a hobbyist - I believe that's the start of a stagnation of that technology as new young engineers never get excited about disassembling and modding hard drives in their free time, and in turn it becomes paid engineers only who, I suspect, are less innovative.
When was the last time you heard someone who had modded their hard drive to, for example, seek faster?