Several people are currently working/have worked on this. Atm
The Lightniing seems to be the only active project. So far it has proven very fiddly to do, mostly due to the large BGA chips requiring special hardware and technique to desolder, reball, and solder to the custom boards without shorting or destroying the chips. The idea is possible, and one of these projects will eventually succeed, but it's almost completely out of scope for a beginner to achieve. The people working on this idea have many years of modding and EE experience under their belts, and I would recommend waiting for one of them to have a successful boot before thinking about dedicating months of your time and hundreds-to-thousands of dollars on prototypes and tools.
