Here is a very short (but in my opinion very useful) how-to for creating an USB boot device, which enables you to boot Debian from your memory stick.

We are assuming that your USB device is indicated by /dev/sda, and that you are interested in Debian stable (other distributions are untested, but should work).

First unmount your memory stick.

Now download the boot.img.gz, which is necessary to make your USB device bootable:

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