I've been playing around with the device and its latest firmware (00.01.14.1) for some time now. It seems that the OSPF6 section of the dynamic routing configuration is quite horribly broken. First of all it is not possible to enable it in the menu, but instead you need to manually edit /etc/config/quagga and add options for (at least) both enabled and enabled_vty under config ospf6 'ospf6'. This in turn shows the same options in the GUI. In any case that should be a fairly easy fix. The missing options could also have been caused by a firmware update not properly updating the config files?
The bigger problem is that the generated configuration file (/etc/quagga/ospf6d.conf) does not work at all. It looks like the generation script (/etc/init.d/quagga) creates the config file in much the same way that it does for OSPFv2. This is wrong, since the two protocols are somewhat different, and as such the configuration file formats are also different. There is no network keyword within router ospf6 but instead it should be area <area-code> range <ipv6-range>. It is also missing the option to attach any interfaces to a given area. This should be added to the UI as well, and generate the following: interface <iface-name> area <area-code>.
Additionally it should be possible to designate the network link-type since by default it is broadcast and in many cases that does not work. It should be possible to change the link-type to point-to-point. This should then generate ipv6 ospf6 network point-to-point under interface <iface-name> definition. And one more thing to add would be the redistribute options.
Fortunately it is at least possible to override all of this with a custom configuration file, but for beginners using the UI this is a showstopper. If anyone does want to properly use OSPFv3 for their routing needs then a custom config is the only viable option. Will this entire thing be fixed in an upcoming FW update, or should I simply continue using custom configs all the way?