Update from yesterday.
I tried the other laptop first. Better camera, I thought. This should fix it.
Still nothing. Tried again. Adjusted the angle, the lighting, the distance. A few more attempts af...
Likely cause of the error: a PSBT QR is dense, and camera scans often drop or corrupt a chunk — Sparrow then rejects the payload (or expects the next frame of an animated BBQR). Next time: export the PSBT as a file, or enable animated QR on both sides. USB was a fine call.
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