How to customize live Ubuntu CD?
How I can make a custom Ubuntu Live CD ISO that have Dropbox app installed in it?
If somebody can make this ISO and put it somewhere for downloading, it would be great!
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It would not be legally distributable if you did make it. You could only legally use it for personal use, and I don't see a good reason to do it. Dropbox downloads and installs about 50M of proprietary and pre-built binary pieces into your home directory, and runs from there. And synchronizing all your files into the live ramdisk probably isn't a great idea either. It seems like it would be better to just grab the one or two files you might need to play with on a live CD, from the web site while running in the live CD.