Please be aware that there is also an OKI B731dn printer which shares a similar model number. Ensure you are looking for e-reader firmware and not printer drivers. ORSiO b731 - 4PDA

Finding the original firmware (proshivka) for the ORSiO b731

can be difficult as the manufacturer is no longer active. However, community resources like 4PDA remain the primary source for these legacy files. Where to Download