Due to high degree of freedom and different mechanism foci, hand and arm exoskeletons are usually developed separately and seldom combined together. Hand exoskeletons are typically more complex mechanisms than arm or leg exoskeletons due to the numerous degrees of freedom encapsulated in the hand and the small anatomical structure involved. This study presents the design of a 12 DOF (6 active) reconfigurable hand exoskeleton for rehabilitation that will be installed on the existing upper limb exoskeleton, EXO-UL8. Given the mechanism architecture, a nonlinear optimization framework minimizes physical footprint while maximizing mechanism isotropy and device functionality.