Netgear R6100 - DHCP doesn't restart after power loss

Hi everybody!
I'm very new to LEDE, so sorry for nub questions)
Bought an used R6100 and then installed LEDE 17.01.4. Also I rtfm'ed a bit and set up a phone usb tethering)
So, everything works just fine, but after power loss router reboots, but I can't connect to it neither by cable nor by wifi.
If I setup IP manually - then I can log in to LuCi, restart interface and then DHCP gets back to life)
How can I make DHCP to restart automatically after power loss?

It's not completely clear which DHCP you are talking about. It could be either one that is giving out addresses to LAN clients (server), or one that is setting the LAN address (client).

If it's the client not assigning an address for the LAN bridge, generally the addresses of the LAN bridge are set as "static" in many users' configurations.

If it is that the DHCP server is not starting, looking at your logs either through LuCI or with

# logread | less

would be the first place I'd look.

LAN bridge address is set to default static ip
DHCP server doesn't restart normally after power loss and doesn't lease IP's to members of LAN
Thank you, will read logs now

By default a DHCPv6 server is also enabled on the LAN, which can confuse clients in a network that you want to be IPv4 only. On the LAN configuration page, click the IPv6 tab under DHCP and disable everything.

If you have bridged the phone into the LAN (which is probably not a good idea) the phone has its own DHCP server. In that case (again, not the best way to do it) you would have the phone doing all address assignment and routing for the LAN users. This will conflict with the router's DHCP server.

The phone should be the WAN device instead.

When I was setting up tethering, I created a new interface for the phone, selected ethernet usb0 and added it to the WAN zone of firewall. Is this a proper way?
And, problems with no IP via DHCP were even when there were no phone)))
About v6 - when I start router normally - both v6 and v4 servers work, no problem to connect phone or computer, on info page i can see v4 and v6 dhcp leases. But after short power loss - no device can connect and get an IPv4. If I try to specify IP manually - no problem to connect)
I'll try to make small power losses and compare logs both with v6 server on and without)))