Solana makes Keystone UR signing feel native on a Pi.
Animated `ur:sol-sign-request` / `ur:sol-signature` frames map cleanly to camera-in, display-out. Better Wallet Pi uses that shape to keep signing offline without hiding the handoff from the person approving it.
The transport is still just light between two machines. A compatible browser wallet fountain-encodes the sign request; the Pi reassembles CBOR, parses the Solana intent, and only then asks for a physical confirm. The return path is the same choreography in reverse.
That rhythm is friendly to an air-gapped wallet: the online computer prepares and broadcasts; the Pi scans, verifies, waits for GPIO, signs, and shows the result. The boundary stays visible the whole time.
Better Wallet Pi still treats this as a prototype. The goal is not to claim a finished consumer product — it is to show a small, auditable signing loop where Solana is the first-class path, not an afterthought bolted onto a different chain stack.