The RetroArch and libretro Cores are now in their own PPA:
hunterk PPA is deprecated for libretro, you should install this stable PPA and update your system, it will replace almost all your cores. This PPA will only have the stable RetroArch version and non-WIP Cores. It will have MAME core too, but only the official releases from upstream, i.e., we will get the Git snapshot after the merge from upstream in the release day or later and freezes it in 0.155, 0.156…
For who does not know how to install a PPA in the system:
sudo add-apt-repository ppa:libretro/stable sudo apt-get update
And then you can install RA + cores + other stuff (like joypad autoconfig files and assets):
sudo apt-get install retroarch libretro*
This will install all the Cores in the PPA, maybe you want to install few of them, so:
sudo apt-get install retroarch libretro-genesisplusgx libretro-snes9x libretro-gambatte libretro-nestopia libretro-mgba
This is just an example. You can see all the Cores using Synaptic or Ubuntu Software Center, and install then from there.
If you like to test new stuff, you can try this Nightly/Testing PPA. It will have the Git version of RetroArch, plus WIP cores like Fuse and Virtual Jaguar. It will have too the Git version of MAME core.
NOTICE: RetroArch now comes with an Online Updater, so you can download/update Databases, Overlays and Shaders there. The testing/nightly PPA automatically update Cores and other things when there are changes in the source. Or you can use the stable PPA, the cores and others are updated periodically.
There are packages only for Ubuntu 12.04, 14.04, 16.04 and 16.10 (precise, trusty, xenial and yakkety respectively), as well Linux Mint 17/18 and other derivatives.
If you are coming from hunterk ppa or if you are having problems with new releases you should delete the config file in ~/.config/retroarch/retroarch.cfg before open RA:
Instruções/suporte em português aqui
There are ARM packages in the PPA, if someone have these boards like Odroid, Wandboard, BeagleBone Black, Jetson TK1 or others (ARMv7 and up), please test RetroArch and the Cores from this PPA and give me a feedback, as I do not have all this kind of board yet to test the packages (I own only an Odroid U3 and C1, and I don’t have much time to test all stuff). Ubuntu for these boards here.
PS: due to debian/ubuntu use libav instead ffmpeg, the recording feature is disabled in the build of Ubuntu 12.04 and 14.04.
For who liked the PPA, I’m accepting donations now
Bitcoin address: 1KcBt7JTjKyqEwGnPEkKRiyVYgq56bgidT
Litecoin address: LQiJyvviF9hQocGgcJr4SJgZ94RAyTRrj5
It’ll help to maintain the PPA & send the packages to Debian repo eventually