The Baochip is packaged in a form of package that is inspectable using IRIS. [1] It does not give perfect verification but it's the best I can offer until we have more open PDKs.

[1] https://bunnie.org/iris

Yes, 1x Vexriscv RV32-IMAC + MMU, and 4x PicoRV32's as RV32E-MC for I/O processing, configured with extensions to enable deterministic, real-time bit-banging without having to count clocks.

It’s not the RISC-V core itself, it’s just some of the surrounding architecture to support the CPU, to turn it into a SOC. So the USB drivers, the AXI memory interfaces, and the analog components, like PLLs for generating clocks, or even the IO pad drivers. These components take the fully open RISC-V core which works in a simulator and makes it work like a normal physical chip would.

With the right equipment it is possible to probe the inside of a chip, allowing an attacker to measure or even alter internal signals down to the transistor level. Expensive, but very useful if it lets you extract a crucial shared secret.

The traditional defense against this kind of invasive attack is to put a grid of sense wires on the outermost metal layer, and measuring whether it has been tampered with: you can't get to the important bits without cutting through the security grid, but any kind of modification to the security grid triggers a self-destruct.