Meh I screwed something up on 3.12.1 that would make cgminer just go idle eventually, so I've posted a hotfix 3.12.2 release.
Con is doing great work, but development is hard, and bugs are inevitable, so this is why we want to thoroughly test everything before we recommend an upgrade.
Still, if you want the best uptime and hashrate, as reported at the pool, you should be running our well vetted 3.9.0h2 version:
Here's the source code:
http://setup.hashfast.com/cgminer-3.9.0h2.tar.gz (MD5: fdef15ae73b180deef74bc51df482eb0)
If you are using our recommended RPI image, this is automatically what you are running.
As of about 15 minutes ago, I'm currently testing a release candidate on my public test system at:
http://setup.hashfast.com/rpi/Watch the hashrate reported at the pool. If it stays good, I'll push it out everyone that wants it:
http://eligius.st/~wizkid057/newstats/userstats.php/17ao2fT7gbnnKYpMd7x29E8p4oGdE87Ahd-Phil