Scotty Allen, a former software engineer, wanted to see if it was possible to build an iPhone from scratch using nothing but its spare parts. Allen quest took him to places like Huaqiangbei in China where most cell phone parts are easily available. And as it turns out, it is indeed possible to build an iPhone from scratch using spare parts.
Allen managed to build an almost new 16GB iPhone 6s from components purchased from various local Chinese markets. The handset is fully functional with even the home button working as intended since the Touch ID sensor and the logic board were purchased together.
The process of building an iPhone from scratch is not easy or cheap, though. Allen spent well over 5 months for the project and spent upwards of $1,000 in components and tools that he needed to assemble the phone together. He did break a lot of components in the process and ended up purchasing tools that were not required. He estimates that he only ended up using around $300 of purchased components inside the iPhone 6s.
Allen could not build the iPhone 7 since its parts were difficult to procure. As for the iPhone 6s, he managed to get most of the parts easily except for the logic board which required him to seek help from many vendors.
If you are interested in the project and want to ask Allen questions, head over to this Reddit thread.