If your looking to restore HPZ in Sonic 2 final, you will need to know how to restore collision, among other things. Many people get confused and think that HPZ uses the same collision as OOZ, but this is not true. Thus making it hard to find the correct pointer. So to restore the collision data you will need to know where the pointer is, and you must change it to the correct location in the ROM. The pointer is located at offset 004A0C, and it points to offset 045A80. This offset that it points to is where the Offset index of level layouts is located. I hope this clears everything up.