Embodiments of the invention provide a method, devices, and system for accessing data in a nonvolatile memory device via a volatile memory device. In one embodiment, the method includes configuring a size and a base address of an overlay window within an address space of the volatile memory device. The overlay window includes a range of memory addresses. The method also includes receiving an access command via a volatile memory interface of the volatile memory device and using the access command to access a memory array of the volatile memory device if an address of the access command is outside of the overlay window. The method further includes using the access command to access the nonvolatile memory device via a nonvolatile memory interface of the volatile memory device if the address of the access command is within the overlay window.