Please excuse the new account, I don't work for them, but https://www.nxmlabs.com . Maybe the hit will cause one of them to chime in.

Their pitch deck was about flashing keys into a root of trust at the fab, then using those as a way to do different types of decentralized or federated firmware integrity attestation. They had some quiet traction with some chip manufacturers and in defense and aerospace and at the time, they were the only ones I thought were really bringing something new to the space.