Hydrogen direct-injection spark-ignition (DI-SI) engines can deliver diesel-class power density, minute-scale refuelling and zero tail-pipe CO₂, an attractive combination for demanding off-road machinery, yet commercial roll-out is held back mainly by infrastructure cost, high fuel price and tank-system complexity rather than by in-cylinder science. Within that strategic context, this work tackles two complementary refinement issues, knock and cycle-to-cycle variability (CCV), whose control remains essential for a market-ready product. Cylinder-pressure-only analysis (CPOA) was performed at 1000 rpm, 200 N·m with λ = 1.8–2.3 and at 1800 rpm, 200 N·m with λ = 1.8–2.5. The low-speed point proved effectively knock-free and exposed CCV and inter-cylinder dispersion, whereas the high-speed point was clearly knock-limited.