Smoke at 120°C (or oven at 135°C) unwrapped 3 hours; then wrap in foil with the vinegar splashed in and cook 1.5 hours more, until the meat cracks when the slab is lifted with tongs.
270 min — timer available in cooking mode
Why this works
The "bend test" beats any timer: lift one end — the surface should crack, not flop (undercooked) or fall apart (past it).