The Digital Millennium Copyright Act was passed in 1998, well before issues like jailbreaking arose. As part of the DMCA, exemptions can be passed as necessary, the latest round of which were announced earlier today. Included in the exemptions is the permissibility of jailbreaking smartphones, but not tablets.
The new exemptions take effect on October 28 and are valid for the next three years. Five types of circumvention are addressed by the exemptions, most of which present the kind of head-scratching stipulations and arbitrariness that make you wonder who is coming up with this stuff. One of the most obvious bits of oddness is the exemption making it legal to unlock smartphones purchased before 2013, but not phones purchased after.
Concerning the legality of jailbreaking: while unlocking smartphones is legal, performing the same actions with a tablet is not. The reason? The definition of "tablet" is too broad at the moment. According to the ruling, "...an e-book reading device might be considered a 'tablet,' as might a handheld video game device or a laptop computer." It was ruled that there is insufficient basis for developing a definition for tablets, which is necessary in order to apply the jailbreaking exemption currently given to smartphones.
Next up is the issue of circumventing ebooks, which is permissible for disability access. The exemption concerns "literary works, distributed electronically, that are protected by technological measures which either prevent the enabling of read-aloud functionality or interfere with screen readers or other applications or assistive technologies." This is an expansion on the 2010 exemption that only permitted circumvention if every available ebook edition contained access controls.
The issue of unlocking just took a step backwards, sadly. The latest exemption removes the previously instituted permission to unlock a phone for use with a new carrier. This change makes it so that only phones originally "acquired from the operator of a wireless telecommunications network or retailer no later than ninety days after the effective date of this exemption" can be unlocked.
Finally, the exemption on ripping DVDs makes the activity permissible for the purpose of using parts of the film in a documentary, noncommercial video, in non-fiction multimedia ebooks offering film analysis, and for educational use by college students and faculty and k-12 teachers in courses requiring the study of film and media excerpts. Decryption is also permissible for disability access, with individuals being permitted "to access the playhead and/or related time code information embedded in copies of such works and solely for the purpose of conducting research and development for the...blind, visually impaired, deaf, or hard of hearing...." Sadly, it's still not permissible to "space-shift," meaning that ripping a DVD on your computer so that you can watch it on your iPhone, for example, is not considered fair use.
[via Ars Technica]