You are of course welcome to download Debian and use it under the conditions of the licenses for the various components of Debian.
License compliance is a complex field and for any mass-produced commercial product you're going to need to retain the services of a professional qualified in that field to succeed. There are a couple of common provisions of software in Debian that you should be aware of: * Many programs require notices to be placed in the notices that accompany your device. * Many programs require that you provide source code to the version of the program that ships with your device or provide a way for users of your device to obtain that device. * The GPL version 3 has special provisions related to consumer devices designed to make sure users have the ability to change the software on devices they receive. This may affect strategies you use for integrity protection, signing and the like. This problem is not unique to Debian or open-source software. In many ways the problem of license compliance is even more tricky for commercial solutions. Regardless, it's not a problem people can solve for you with a few messages on a mailing list. Good luck, and we're glad you find Debian useful. Thanks for letting us know! --Sam
