Make the marinade: In a medium bowl, combine mashed garlic, lime juice, oregano, soy sauce, olive oil, salt, and black pepper.

Wash the pork shoulder in vinegar and water.

Pat the pork shoulder dry with paper towels.

Place the pork shoulder on a cutting board, fat side up.

Cut and open the fat layer like a book, leaving it attached at one end.

Poke 1-inch deep holes into the meat on all sides (about 20 holes).

Place the pork shoulder in a roasting pan, skin side up.

Rub the marinade all over the pork shoulder, making sure to work it into the holes.

Return the skin to its original position.

Score the skin with diagonal cuts.

Sprinkle salt over the skin to taste.

Cover tightly with aluminum foil.

Refrigerate for 24 to 48 hours.

Remove the pork shoulder from the refrigerator 45 minutes before roasting.

Preheat the oven to 475 degrees F.

Add a little water to the roasting pan (about 1/2 inch up the sides).

Cook the pork shoulder uncovered for 1 hour.

Turn the oven temperature down to 225 degrees F.

Tent the pork shoulder loosely with aluminum foil.

Cook for 8 hours.

Remove the foil and cook for 1 hour.

Let the pork shoulder rest for 10 minutes before slicing.