Major flexible electronic products today are only flexible between the high-performance silicon components. They lack the true flexibility envisioned for printed systems. Silicon components in conventional packages and bare silicon die are too thick and rigid. Mounting these components on hybrid printed systems compromise functionality, flexibility, and thickness. Advanced semiconductor packaging technology bridges the gap between flexible and conventional electronics. Semiconductor-on-Polymer™ (SoP) advanced packaging technology is currently being used to produce complex system-on-chip (SOC) ICs that are commercially available and being introduced in advanced FHE products. The new capability bridges the gap between printed, flex and conventional heterogeneous electronics with commercial production of SoP packaging and FHE assembly started in 2019. This presentation will report and illustrate how SoP enables ultra-thin and fully flexible printed foils such as silver on PET, copper on polyimide and thin flexible interposer applications. Multiple ultra-thin die mount FHE approaches will be shown including ACA, ACF, and solder on flexible films. Ultra-thin SoP packaged flexible ICs with dense memory, wireless communication, and complex logic will be discussed. The presentation will report on new production capacity that has come online in 2019 for ultra-thin advanced IC packaging and automated ultra-thin flexible assembly.