D-branes on T4/Bbb Z2 and T-Duality

In this note we discuss D-branes on T4/2 using the boundary states formalism. Explicit formulas for the untwisted boundary states inherited from the underlying T4 and twisted states corresponding to branes wrapping collapsed 2-cycles at the orbifold singularities are given. The exact CFT description of the orbifold makes it possible to study how the boundary states transform under Ri1/Ri transformation on all directions of the underlying T4. We compare their transformation law with results obtained from world volume considerations.