In theory that's possible true but in practice on an iPhone I highly doubt a DIY can do "the exact same thing". For one there are important ports we can't acce

In theory that's possible true but in practice on an iPhone I highly doubt a DIY can do "the exact same thing". For one there are important ports we can't access, like JTAG testing the SOC. And there is a whole other factory OS which we have no idea what it does and why.