Mostly just by using better components and beter internal cooling (=thicker design). You can find same chips (=same function) made for consumer electronics, au

Mostly just by using better components and beter internal cooling (=thicker design). You can find same chips (=same function) made for consumer electronics, automative, aeronautic and military, all with different temperature and humidity ranges. I'm not sure about mobile phone CPUs/SoCs, but automotive equipment is a lot more resilient to voltage spikes well above the normal 12-14V.