I got my new Netgear R7800 from old ASUS RT-AC66R with ASUS merlin and uploaded this R7800-lede-r5882-dd975d15a7-20180117-1758-sqfs-factory.img from your dropbox via tftp2.exe and no problem at all. My internet is at full speed, both 2.4ghz and 5ghz wifi are working fine. However, there is the only one problem I've been dealing with is trying to make ipv6 working permanently. I'm still very new to LEDE, still learning how to use it. https://www.dropbox.com/s/hhnx5d39gjw5gv9/waterfox_2018-01-22_10-12-54.png?dl=0
my ISP is Spectrum, 100/10Mbps. Btw, I used to had both ipv4 and ipv6 working permanently with ASUS merlin for long time.
Tried stateless. It worked for a few minutes then dropped. Also tried stateful+stateless. It's about the same thing. I still don't understand how ipv6 configuration works. I tried to read the LEDE ipv6 configuration documentation, but it's still confusion for me.