Has anyone considered that, due to its hard soldered PoP/SoC combination, it might make a quite good HSM. It could load the encrypted contents from a LUKS filesystem on the SD card. This would then be unpacked into memory and run from there.
A hardware security module (HSM) is a type of secure cryptoprocessor targeted at managing digital keys, accelerating cryptoprocesses in terms of digital signings/second and for providing strong authentication to access critical keys for server applications. These modules are physical devices that traditionally come in the form of a plug-in card or an external TCP/IP security device that can be attached directly to the server or general purpose computer.
The goals of an HSM are (a) onboard secure generation, (b) onboard secure storage, (c) use of cryptographic and sensitive data material, (d) offloading application servers for complete asymmetric and symmetric cryptography. HSMs provide both logical and physical protection of these materials from non-authorized use and potential adversaries. In short, they protect high-value cryptographic keys.
Just an idea….