What I knew about Knox 10y ago was that it was an applet within the TrustZone that samsung adopted, and I didn't think they got an actual fuse. Think of it as a

What I knew about Knox 10y ago was that it was an applet within the TrustZone that samsung adopted, and I didn't think they got an actual fuse. Think of it as an HSM/Vault so Android would essentally use it as that. The secrets in the SE/HSM would ensure anything sent to it by the OS would be derived from that unique hardware protected key. There are a couple of ways and a few factors of doing a secure environment in the OS based on this. Essentially, each device gets a basic provisioning key at manufacture that authenticates/attests it back to the OEM, and then it gets "personalized" with a set of new keys unique to the device, derived from either that provisioning key, or secrets at the OEM's HSM. The stream cipher that they broke using the IV weakness would plausibly have used these personalization keys (post provisioning/manufacturing), and not ones protected by a fuse from manufacture. Again, speculative based on design principles, but there's a short list of ways this stuff works.