Wow, what a great time to come across this thread!

I also have been trying to use TPM on a RPi3 and was seeing the exact same problems. I, however, was using OE and meta-measured to build my images. It turns out that meta-measured/recipes-tpm/tpm2-tools wasn't DEPENDing on tpm2-abrmd, so all builds as a result were not enabling the tabrmd TCTI.

Hence: https://github.com/flihp/meta-measured/pull/68

By the way, what's the difference between "abrmd" and "tabrmd"? It seems rather confusing that the tools list "tabrmd" as a TCTI, but in order to use it one specifies "abrmd". Something feels wrong.

# tpm2_pcrlist -v
tool="tpm2_pcrlist" version="" tctis="tabrmd,socket,device,"

# tpm2_pcrlist -T tabrmd
ERROR: Unknown tcti, got: "tabrmd"

# tpm2_pcrlist -T abrmd
sha1 :
  0  : 0000000000000000000000000000000000000000
  1  : 0000000000000000000000000000000000000000
...