The OI-on-SD (live) version of OpenInkPot
is the once that can co-exist with any standard firmware. Some people have found this to be unstable, but it works well for me.
All Hanlin V3's can run any firmware. The current firmware probably includes MOBI DRM (encrypted ebook) support. Astak will very soon release a new firmware that will drop MOBI in favor of Adobe PDF/ePub DRM, see Adobe Digital Editions for EZ Reader
. I suggest waiting for this firmware, although if you have many MOBI ebooks already you may want to stick with a MOBI-DRM firmware. So far as I know, most firmwares are close to the standard Jinke firmware
the exception is LBook