Not totally sure where to post this, but just some quick guidance for anyone else who wants to install LEDE on these.
The charter models are very cheap, so I picked one up. Wireless is barely functional on LEDE, but I personally don't need WiFi.
I actually updated to the latest netgear 1.0.4.24 firmware by flashing dd-wrt first with http://www.desipro.de/ddwrt-ren/K3-AC-Arm/Initial/dd-wrt.K3_R6300V2CH.chk and then installed the official 1.0.4.24. Unfortunately I realized 1.0.4.24 does not have telnet support, so I went ahead and downgraded to 1.0.3.8. If you have the stock charter firmware then you don't need to bother with any of that.
I used this utility http://www.mediafire.com/file/tcen54n6k66yu58/telnetenable2.zip
And ran commands from here
telnetenable 192.168.1.1 ROUTERSMACADDRESS admin password
Then connect via telnet and type
burnboardid U12H240T00_NETGEAR
nvram set board_id=U12H240T00_NETGEAR
Then you can flash now flash LEDE.