Been weighing this up for the Favilla KEY as well, and it's where I've landed. Two versions. The factory-signed one for people who want the chain of trust handled and a device that will only ever boot what Favilla signed. And an open version that ships with the boot keys unburnt, so you generate your own, sign your own builds, and the device trusts you and nobody else. The trade is simple. Open means nobody can lock you out, including me, but the security of the thing now rests on how well you generate and guard those keys. Honestly that's how it should work anyway. A hardware wallet is about taking custody of your own keys, the boot key is just one more.

Open keys only buy something if the build is reproducible - otherwise you sign a binary you can't audit. Two things bite later: the boot key lives offline, apart from the wallet seed, and you need a reflash path if lost. We build that: free, byte-reproducible, docs on GitHub.