Identify Model (Xbox 360)

Identify which console you have based on the CPU. If it has no silver integrated heat sink, it is a Winchester and cannot be modded at all, full stop.

For all other versions, you can mod them and identify which you have by the power supply.

If you have a Corona, you need to further identify its specific version (as it changes how the mod is done) by looking at the NAND chip far below the CPU.

You can also identify if it is a Corona or Trinity by looking at the debug headers. Corona (shown here) has one header horizontal and one vertical, and the Trinity both are vertical.