Abstract: Apparatuses, components, devices, methods, and systems for an adjustable firmness mattress are provided. An example rectangular shaped adjustable firmness mattress extends lengthwise from a head end to a foot end, widthwise from a first side to a second side, and depth-wise from a top side to a bottom side. The example mattress may include an adjustable firmness support layer disposed between the bottom side of the mattress and the top side of the mattress. The adjustable firmness support layer may include at least one rotatable assembly having an orientation-specific firmness, a bridge assembly disposed between the at least one rotatable assembly and the top side of the mattress; and a support assembly disposed between the at least one rotatable assembly and the bottom side of the mattress.