D-Link DIR-810L connect failures

Hi, I'm having problems with 17.01.4 on an D-Link DIR-810L (HW version A1).

I've successfully(?) flashed 17.01.4 after following the instructions on
https://openwrt.org/toh/d-link/dir-810l , I had to take the extra steps to append a signature (command I used: ./ncc_att_hwid -f lede-17.01.4-ramips-mt7620-dir-810l-squashfs-sysupgrade.bin -m "DIR-810L" -H "A1" -r "WW" -c "1.0" -F "1.02B22" -a).

Now my DIR-810L boots LEDE/OpenWRT, and when I NAT the traffic from the WAN interface through my computer and out onto the internet and I tcpdump traffic I see it's requesting and getting a DHCP address from my computer, and it also starts talking to NTP servers (0.lede.ntp.org if I recall correctly) and getting answers, so the NAt in my computer is working.

I have to configure the interface used for the DIR-810L to use VLAN (modprobe --first-time 8021q ; ip link add link eth0 name eth0.2 type vlan id 2) and configure udhcpd to listen to eth0.2, but then the traffic in the previous paragraph wo
rks.

So it seems LEDE/OpenWRT does work.

However, I can't reach the router in any way.

It seems all five interfaces on the DIR-810L are one common virtual interface. A
ll use VLAN 2 and none answers on any port (just as if they're all WAN interfaces).

Any ideas?

I've also tried to reach the emergency firmware flashing page as described on LEDE/OpenWRT's DIR-845 page (and on D-Link forums) using a large variety of interfaces (WAN and all LAN), IP addresses (192.168.0.2 and 192.168.0.10 on the computer and http://192.168.0.1 and http://192.168.0.101 as addresses on the router I'm trying to reach) , and seconds-to-hold-the-reset-button but that doesn't work for me (it does work on my DIR-845 though). The DIR-810L never replies to ARP requests when booting to emergency flash mode.

I'm really stuck here and would appreciate any help.