I can't tell if this is sarcasm. TrustZone is a technology for resource isolation. At an extremely high nontechnical level, it's conceptually similar to memory protection.
On Raspberry Pi for example, you can write the hash of your own public key to locations 47-54 of the OTP memory block:
https://www.raspberrypi.com/documentation/computers/raspberr...
Here's the QuickStart for the entire process: https://github.com/raspberrypi/usbboot/blob/master/secure-bo...
Note that the Raspberry Pi does not have a full TrustZone implementation to protect secure mode memory, etc. But it is a widely available device with good documentation and allows developers to experiment with and learn about the basics of TrustZone architecture.