The only way around that would be for Trezor to ship their devices with some sort of attestation function (e.g. a private signing key to which they publish the public key, or sign it via a PKI and include a certificate) and validating that, not just the statement "I promise to be running the authentic firmware", a hash over the firmware, a complete firmware dump or anything else not involving a challenge-response or uncloneable function of some sort.
leaked key seems worse in that people will think they have this security measure working for them while they don't. Without this measure there is no illusion at least
The only way around that would be for Trezor to ship their devices with some sort of attestation function (e.g. a private signing key to which they publish the public key, or sign it via a PKI and include a certificate) and validating that, not just the statement "I promise to be running the authentic firmware", a hash over the firmware, a complete firmware dump or anything else not involving a challenge-response or uncloneable function of some sort.