The development towards ubiquitous network access requires innovative solutions to get remote areas included, especially rural areas of developing regions. We report on recent progress in the Serengeti Broadband Network, one of the first pilots established in the Tanzania ICT for Rural Development programme with the mission to design and validate a method to establish sustainable broadband markets in under-served areas. The challenges include ownership and leadership, sustainable business models, robustness of network components and poor or non-existent supply chains, including power supply.