Foothold system on a sloped roof includes first flashing block with hole, second flashing block with hole, moveable foothold with hook portion removably inserted into first flashing block hole and lower portion comprising a step portion extending down-roof from hook portion, the moveable foothold moveable from first flashing block to second flashing block via unhooking hook portion from first flashing block and hooking hook portion to second flashing block; flashing blocks may include mounting portion to receive mounting foot for photovoltaic array, and/or step portion sized to receive and support weight of foot of human working on sloped roof.