I am preparing a document in detail showing light on the boot sequence of Linux right from pressing of Power-on button the host to the login prompt appearance.
It would be great if we could combine and collate that right answers here into a single place of reference. Please include any details worth possible to note during the startup. Once the document gets complete from all the points, I will post the document details here as well and update the link in the question.
Please consider all possible scenarios like booting from disk, booting from usb, booting from network on a disk-less client where the rootfs(/) is on network.