Methods and apparatus are described for adding one or more features (e.g., high bandwidth memory (HBM)) to an existing qualified stacked silicon interconnect (SSI) technology programmable IC die (e.g., a super logic region (SLR)) without changing the programmable IC die (e.g., adding or removing blocks). One example integrated circuit (IC) package generally includes a package substrate; at least one interposer disposed above the package substrate and comprising a plurality of interconnection lines; a programmable IC die disposed above the interposer; a fixed feature die disposed above the interposer; and an interface die disposed above the interposer and configured to couple the programmable IC die to the fixed feature die using a first set of interconnection lines routed through the interposer between the programmable IC die and the interface die and a second set of interconnection lines routed through the interposer between the interface die and the fixed feature die.