There is a specific algorithm you are supposed to use to calculate the fingerprint. It involves using the secp256k1 algorithm and I think possibly because of memory constraints, I had issues getting that library to run on the device.
It also wasn't giving very helpful feedback, I think the device just crashed after attempting to perform a memory allocation step.
oh, fingerprint would require generating the public key, it's a truncated hash of the pubkey usually
surely there must be a memory constrained version for deriving a public key using secp256k1?
it doesn't require that much memory actually, so the library isn't well coded
I'll jump back on this project some time this year. Hopefully I'll have more luck. I also have had advice on debugging hardware I can buy to help me zero in on the root cause.
I'm a little out of it depth with all this low level c++ coding, and most complex for me: compiling for non standard CPU architecture.
it would be easier if it was C probably, C++ complex syntax often masks underlying wasteful abstractions
