The UEFI talk [1] and EFI bootkits for Apple MacBooks [2] are both really interesting. ( Both are about flashing firmware. )

And for a rather impressive demonstration how fucked the western IP law is, bunnie's and Xobs talk about the MT6260 SoC. [3] (They try to implement a free as in freedom OS on a cell phone SoC which is open in a Chinese context. The hops they have to jump through are rather ridiculous.)

[1] http://media.ccc.de/browse/congress/2014/31c3_-_6129_-_en_-_...

[2] http://media.ccc.de/browse/congress/2014/31c3_-_6128_-_en_-_...

[3] http://media.ccc.de/browse/congress/2014/31c3_-_6156_-_en_-_...

I liked:

Iridium Pager Hacking. Turns out messages are not encrypted at all, and can be captured by any one over wide geographical ranges (~1000 km). https://www.youtube.com/watch?v=xCf5JFpOkDs&index=36&list=PL...

Security Analysis of Estonia's Internet Voting System. https://www.youtube.com/watch?v=JY_pHvhE4os&index=37&list=PL...

AMD x86 SMU firmware analysis. Not watched it yet, but topic seems interesting. https://www.youtube.com/watch?v=yE_PMcwltzo&index=16&list=PL...

And of course the SS7 talks showing glaring flaws in mobile networks:

Mobile self-defense. https://www.youtube.com/watch?v=GeCkO0fWWqc&index=10&list=PL...

SS7: Locate. Track. Manipulate. https://www.youtube.com/watch?v=lQ0I5tl0YLY&index=4&list=PLO...

SS7map: mapping vulnerability of the international mobile roaming infrastructure https://www.youtube.com/watch?v=SfPC9IHCW-U&index=27&list=PL...

"Fernvale: An Open Hardware and Software Platform, Based on the Closed-Source MT6260 SoC"

Interesting attempt to bridge Chinese and Western cultures towards open collaboration.

https://youtube.com/watch?v=msrTR3hNDQM

I particularly enjoyed:

Reproducible Builds: on creating a build that produces the same exact binary on every machine so people can verify the integrity of the binaries published by an open source project).

Snitches get Stitches: pen testing switches used in utilities like furnaces.

And of course the SS7 talks.