Jumpnow Technologies, a software consulting group and a Gumstix Verified Design Consultant recently posted an pair of instructional articles to help DuoVero developers get things done.
Building Duovero Systems with Yocto shows you how to assemble the meta layers and development tools you need to generate your own custom flavor of DuoVero-compatible Linux. Everything from build machine setup to SD card prep is succinctly covered. Now Gumstix has its own guide at gumstix.org, and our own yocto resources in our public repositories but the guide from Jumpnow is great for getting you started with application-specific custom builds.
Duovero Real-Time Clock answers the question "How do I set up trickle-charging on the Parlor's RTC module?" I know, that's probably been wracking your brain for months. TI's TWL6030 has backup battery charging capabilities, but it is disabled by default. Jumpnow's guide provides helpful instructions and a Linux 4.4 patch that gets the RTC registers configured to do the job.
Thanks to Jumpnow for providing these resources and many other instructional articles for Gumstix COMs, Raspberry Pi, BeagleBone Black, and more.
AS A DISCLAIMER: I have to point out that charging Li-Ion and LiPo cells can be dangerous and lead to damage, fire, or physical injury. If you enable trickle charging on any Gumstix board, you do so at your own risk.