How DOES one load an OS onto a phone?

[a5cent]

Manufacturer flash phone OS OEM: https://dev.windowsphone.com/en-us/OEM/develop#option3

Nice link!

Just to clarify though, what is being explained is how the OS is setup and packaged. It's not so much about how OEMs get the OS onto their devices. Using PID requires that software is already on the device. PID is heavily used during device development, but not during manufacturing.

If you can use PID, you can also use Nokia's recovery tool.