Re: So Open Source is the answer?
> Can a third party prove that there's no backdoors in the executable even if the code they give is clean of backdoors?
Assuming the software is fully open-source, it should be possible to recompile from code, and install the locally compiled binary. Assuming your compiler isn't also a DJI product, this should give you near 100% certainty.
This is how hoby-level drones currently work - Betaflight is one of the primary bits of software used for racing drones, and it is fully open source. It's trivial to compile it from source (and many people do, to make it run on unusual hardware or to disable / enable different bits of it). Although DJI's offering is more complex, it could work the same way.