At the current time THERE ARE NO BUILDS FOR ALLWINNER DEVICES released by the LibreELEC team. Please save your breath and our time by not creating "is <device> supported?" posts, because whatever the device is, it's not supported. Elsewhere on the internet there are some LE builds circulating. These appear to be based on old kernels, old drivers, old hacks for Kodi, and we don't know what else. They are nothing to do with us and we have no knowledge about who is creating them or why anything does or doesn't work in them.
The current Allwinner development effort in our GitHub repo centres on modern kernels and uboot, and will ultimately use V4L2/mem2mem decoding with GBM/DRM rendering in Kodi. Some of this work depends on future V4L2 kernel changes not scheduled to be finalised until Q2-2018-ish timeframe, and at the time of making this sticky post an interim video driver is only partially written. TL;DR: If you clone the allwinner development branch in our github repo at the moment you will not get a working image to play with. The core OS probably boots but Kodi will not run. Again, save your breath and our time and please wait patiently until there are official announcements and alpha/nightly type releases have started.
UPDATE: 23/7/2018 ref. to: Delivery of Allwinner VPU driver main goals - Bootlin's blog
As part of their work on the DRM driver the bootlin team have shared an LE image. At the current time their codebase is a little behind our master branch and further behind current Kodi master branch. The majority of their code has been actively developed in collaboration with our developers working on other SoC platforms, but we need to adapt their concepts in a couple of areas so approaches remain unified over multiple SoC/GPU types. We are also waiting on mali GBM libraries to be released for the H6 chip, and we haven't spent much time on distro packaging. Most SoCs have a long list of minor hardware support niggles when bumping to mainline kernels (device trees, drivers, etc.) and despite a sizeable and active user community we expect Allwinner hardware to be no exception. So we are still some way from releasing public images, and we are only just starting to think about specific device support. As a broad sweeping rule LE strongly favours 'boards' over 'boxes' as they tend to be better made and better supported devices, so that's where our focus will start and likely remain.