Dual fuel internal combustion engines (ICEs) using diesel and fuels that are vaporous in normal conditions are collecting consideration for two motives. First is the occasion to achieve diesel-like power density ϕ and fuel conversion efficiency η steady-state, and similar transient performances. Second, is the chance to deliver better than diesel engine-out emissions, for CO2, particulate matter, unburned hydrocarbons, and nitrous oxides. A high-pressure (HP) cryogenic liquid injector is proposed for H2 and applied to a high compression ratio high boost ICE featuring 2 direct injections (DI) injectors per cylinder, 1 diesel, and 1H2. Super-turbocharging (mechanically assisted turbocharging) is employed to make better steady-state performances, especially low-speed high-load, but also high-speed high-load, and transients, principally eliminating the turbo-lag. This work aims at evaluating the benefits of further increasing the injection pressure of the cryogenic hydrogen in a specific dual fuel diesel-hydrogen engine setting. With the proposed 1600 bar injector, this ICE delivers top η>52%, and higher η>40% over most of the speed-load range, with the option to further increase ϕ vs. the baseline diesel working less lean at top loads and adopting mixed premixed-diffusion combustion modes.