India, Sept. 8 -- Making a display bend twice is no longer the defining challenge for tri-fold phones. The harder task is fitting hinges, batteries, cameras, antennas, cooling hardware, and high-performance silicon into three thin sections without creating a device that feels more like an engineering prototype than a phone.

That shift matters because the category is moving beyond proof-of-concept hardware. Mechanical reliability, thermal control, component thickness, software scaling, and manufacturing consistency are becoming more important than simply producing the largest foldable screen.

The Mate XT 2 Ultimate Design offers a useful look at that transition. Its most important changes are buried beneath the display, where Huawei has ...