Apparently, TI has been trying to use the DMCA and U.S. copyright to stop third-party developers from working on or distributing alternative operating systems for some of their calculators.
The stock OS that TI is shipping uses a cryptographic signature process to prevent the user from booting any non-TI operating system. However, the signature verification was broken and people have managed to run their own software, developed independent from TI's software.
TI is not claiming that the DMCA DRM restrictions are applicable to this case, and that the signature process constitutes a DRM system. This is obviously bogus to any technical person. The TI firmware is not encrypted, and you can copy and run it on other hardware or an emulator if you please. The protection mechanism is rather the other way around: The hardware authenticates the OS.
The Electronic Frontier Foundation has taken up the case and is defending some of the affected people from the community against TI.
As you can see from the EFF letter to TI, the EFF cites a number of precedent cases where the courts have ruled in very similar cases that such mechanism is not a DRM system on the software.
That precedent summarized in the EFF letter is actually very exciting to me. It is directly applicable to all kinds of locked-down devices. Let's assume we're talking about a Linux-powered device like the Tivo, Motorola MAGX phones, the G1 phone (non ADP-Version). They all use GPL Licensed software that is cryptographically signed to prevent the user from exercising his Freedom to run modified versions of the GPL licensed program.
Precedent that indicates that such a system does not constitute DRM as protected by the DMCA means there is a lot more freedom for people to break such systems and freely talk about how it was performed, as well as distribute alternate software images for the respective devices - as long as the code they use is either their own or Free Software and does not contain proprietary bits of the device vendor.