A manufacturer should always be 100% liable for the product they make, when used as intended under intended conditions. Warranty and fitness for purpose should not be waivable, ever. In software or hardware.
Ok, how would this work in software, since you can't prove something bug-free? You can't prove it bug-free in general, but you can prove certain cases bug-free. Also, just as imperfections happen when making anything, warranty doesn't imply 100% of theoretically valid circumstances are going to get the results you want. Equally, just as nobody expects an unmaintained car with no oil or fuel to run, nobody should reasonably expect open source to work without patches and necessary versions of support libraries.
One can also argue that open source is a prototyping system. You would expect a breadboard or an S Deck to work as expected, you would expect transistors and capacitors to do their stated tasks within the stated parameters. You do not expect the makers of any of these parts to provide added insurance against your flipflop circuit gaining intelligence and seizing control of the world. If you're a good enough inventor to build a flipflop with AI capabilities, YOU provide the insurance.
Same goes for all drones, robots, rovers and UAVs. The manufacturer should be 100% liable for what they make. Modders should be 100% liable for what they mod and all direct impacts.
(So if you turn a camera holder into a rocket launcher, you are responsible for the rocket launcher, issues due to the physical and electrical demands of that rocket launcher, etc, but the manufacturer is still responsible for any communications systems, flight control, etc, since these do not fundamentally change. It is the manufacturer who decides what to hard-code and what to measure, it is the manufacturer who decides on whether to add voltage regulators - since surges can happen under normal conditions, etc.)
Deaths caused - if it's a pre-mod design flaw, the manufacturer is responsible. Same as it would be if your car spontaneously exploded. If it's a post-mod design flaw, the modifier is responsible. If it is a design feature specifically used as such, the user is always responsible. (The qualifier is because guns are designed specifically to kill. If the gun blows up in your hands and kills you, when you don't pull the trigger, the manufacturer should not be able to argue the gun functioned as designed. If you try to kill someone and the gun kills you instead, the manufacturer should not automatically be liable, although they may be found such.)
The next stage in drone development is obvious. Operators suffer PTSD at the same rate as fighter pilots. Computers can be fooled, as Iran has demonstrated. Rat brains can already operate flight simulators. Ergo, rat brains will be installed in drones, after being trained to trigger specific responses that can be treated as fire commands when specific objects are seen. This is easier than programming a computer, and as rats are easy to produce without rare materials located in potentially hostile countries, cheaper and more reliable.
Won't there be objections? As if drone strikes aren't controversial! What do plebs matter to the military?
As for home inventors, there are already kits to control cockroach brains and games that read electrical impulses from humans. I can't imagine it will take long for someone to figure out how to use insect brains to control UAVs.
At the point where non-human nervous systems operate UAVs, is the inventor responsible for the free will decisions made by the other brain?
Using conventional lets-blame-someone logic, the answer is no. No matter what the training, no matter how small the other brain, it always had the opportunity to say no. No matter how xenophobic or genocidal it is, at the start or end, it always made the choice.
Using a scientific concept of cause-and-effect, which is a many-many web of weighted interactions, you're damn right you're responsible. Whether the daleks you have invented are under your control or not. You cannot escape your guilt by saying they did it.