If the meat did not come scored from the butcher, use a craft knife or box cutter to score the skin in 1/2-inch intervals.Rub salt liberally all over the skin, making sure to work it in between each of the cuts in the rind.
Place the roast into roasting pan and place in the oven. After 40 minutes, begin basting the roast with the pan drippings every 20 minutes. After 90 minutes, remove the roast from the oven and increase the heat to 475°F.
Transfer the roast to a foil lined, rimmed, baking tray. Return the roast to the oven for about 10 to 15 minutes to crisp up the crackling. Keep an eye on this step so the crackling doesn't burn up. It crisps up rather quickly under the high heat. The new baking sheet is important so as to not burn and smoke the oil in the pan juices you've collected thus far.
Let the roast rest for 10 - 15 minutes to allow the juices to redistribute before slicing. Use the slices in the crackling as an easy guide for slicing the meat.