How can I make a full, restorable image of my pre-root Android hard drive, as in Clonezilla?

Question

In Clonezilla, one boots OS-1 (Clonezilla) on Drive-1 (USB stick) in order to make a full, restorable image of Drive-2 (which may contain OS-2) on Drive-3 (the backup drive). One does not need any permissions or "root" on Drive-2 or OS-2 in order to make this copy. In fact, one could perform this procedure on any drive at all, including your drives, without knowing any of the relevant passwords!

• Question #1: How can I use free software on OS-1 (Linux, Windows, etc.) to make a full, restorable image of Drive-2 (brand new, untouched Android phone), including ROM, bootloader(s), and any other sections, partitions, etc.?

  If you believe the answer is, "You can't," then..

• Question #2: After I have rooted, how can I restore Drive-2' (the rooted and thus altered Android phone) to its original state, Drive-2 (brand new, untouched Android phone)?

  If you believe the answer is, "You can't," then..

• Question #3: Why should I not worry about this?

It seems odd that one must alter Drive-2 (rooting process) in order to make a copy of Drive-2', but it seems like ClockworkMod's NANDroid images (and others) do exactly this by requiring root. Perhaps I am simply confused.

Answer 1

1. In general, you need to root the device to make a full backup. After you've rooted the device, use nandroid (which it seems you already know about). You can make a backup that doesn't include the OS by following one of the answers to How do I perform a full pre-rooting backup of an Android phone?

2. By flashing the stock ROM and recovery for your device, and wiping the userdata partition. See Where can I find stock or custom ROMs for my Android device? to find the stock ROM for your phone.

3. Because if you've broken the OS, recovery, and bootloader on your device sufficiently that you can't just flash a ROM image the usual way, there's no way you'd be able to restore any kind of backup image.