This dirt cheap 4G LTE modem on a USB stick can be hacked to run mainline Linux - Liliputing
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Amazon.com: LTE - The UMTS Long Term Evolution: From Theory to Practice: 9780470660256: Sesia, Stefania, Toufik, Issam, Baker, Matthew: Books
Amazon.com: LTE - The UMTS Long Term Evolution: From Theory to Practice: 9780470660256: Sesia, Stefania, Toufik, Issam, Baker, Matthew: Books