But secure-boot is hard and expensive. Getting the fuses set is something (I guess) will have to be done by xilinx in the factory, which is an extra service, not cheap.
This is BS. No extra service is needed, everything can be done via JTAG just like regular programming/configuration.
There there no need to be cross.
But please lets remain civilized. For one, enabling the feature via the fuse is easy, sure yes. But I cannot find any indication in the manual about the secure vault (other then the graph) where the _private_ key is stored. Or how to set it. I'll agree I have not studied the manual in depth of course.
Now I know how this works a little on Texas Instruments HS parts (High Secure) and there it's simple. Encryption is a chain of trust, and TI says 'we will program the keys securely, nobody else has access to the keys, but you need to trust us'. Trusting some factory floor employ not to leak the key is of course, a risk.
So I would assume it works the same way here. But sure, maybe a user can program the fuses for the RSA key themselves, or maybe they can store the key in Battery Backed RAM themselves. Surely possible.
Just one problem I can imagine if the user can burn the RSA key fuses themselves, what stops you from burning ALL key fuses, effectively turning the fuse into 0xfffffff? Or worse, use jtag to read back the fuses? So again, it would surprise me that a user (developer) gets to write into the actual vault, and would imagine this to be left to xilinx only. Just like you do not have any access whatsoever to the BootROM (access is disabled after execution).
But please do point me to the page where they have this information; I'd love to read up on it, I do.
Understanding how it all works and comes together, is also; not for the faint of heart.
Reading documentation is all it takes. But even if we suppose they are somehow too stupid to figure it out (yet somehow manage a several orders of magnitude more complicated task of designing an actual system in FPGAs), they could always enlist Xilinx FE to help them out.
I suggest you stop projecting. They clearly can read documentation, and I'm 99,(9)% sure they leave devices open on purpose.
Different task, different people, different skill. They are a _hardware_ company, and while *I* feel that VHDL/Verilog programming is just a different skill of programming; it tends to be done by EE's. As such bringing up a secure linux with UI is not their problem.
But sure, this is only projecting and suggesting, I never claimed otherwise. But since you have inside details; please do share more. We can all learn from that.