I found it very easy to install a current snapshot on this device via the normal sysupgrade process. But note that opkg is not available now, so to get Luci up on the device use apk instead. apk uses the command "add" not "install." I had no problem getting Luci and all the usual things I use running.
(I was having crashes with the Gl.inet firmware, so pleased to be able to use vanilla and up-to-date OpenWRT.)
jeremy