The surge in Internet usage and connectivity worldwide coupled with the emergence of 5G mobile communications has amplified the need for a scalable and sustainable telco networking model. This paper outlines our Open Broadband trial in Brazil and the journey to open software and whitebox hardware as a practical approach to scaling fiber access networks enabling integration into a software-defined network controlled environment while transitioning away from vertically integrated models featuring black box passive optical network (PON) solutions. A key part of this journey is multi-PON capable whitebox optical line terminals (OLTs) with combo-PON (C-PON) optics that play a key role in bridging the transition from G-PON to XGS-PON.