After a sysupgrade you can restore the setting backup file you generated before the upgrade from Luci's System → Backup/Flash Firmware page.
OK, i flash Lede FW. This work. Than i flash backup from lucis system.
And router break down...
Any idea?
Thanks
/router TPLink WDR3600
/old lucis system openwrt-ar71xx-generic-tl-wdr3600-v1-squashfs
/new lede system lede-17.01.0-r3205-59508e3-ar71xx-generic-tl-wdr3600-v1-squashfs-sysupgrade.bin
If there is too wide difference between the old and new version, the old system's settings will not work properly. Likely some network settings have changed too much in between.
You will likely need to rebuild your settings from scratch.
How to rebuild settings?
By editing config files in /etc/config manually, or by using LuCI GUI.
You can e.g. extract the backup .tar.gz archive with an archive tool on your PC and look at the config files to see the old config as a reference.
Impossible to connec via lan, see terminal screenshot.
DHCP, factory reser, failsave mode - all not work
Tomorrow i try conect over serial like this: https://www.youtube.com/watch?v=t35Pei_eb6o
maybe the only possible solution.... 
Here's a thing you can still try:
Do you get any reply from ping6 ff02::1%eth0 ? Ideally one of the replies is from an IP other than fe80::e2cb:4eff:fe46:b623 - if you get such a reply it is the router.
Try SSH to it using ssh root@fe80:...%eth0 then.
Today some "new" IPv6 addr.
Ping is not reached at all...
You need to use ping6 not ping.
Sorry my mistake.
Some addr. ping work. All addr. ssh not work.
For addresses beginning with fe80:... you need to append a scope id, %eth0 in your case. Also you attempt to SSH to the IPv6 addresses of your pc, this is not what I meant.
use ping6 ff02::1%eth0 to discover all IPv6 hosts on your lan, here's an example from my pc:
jow@pc:~$ ping6 ff02::1%eth0
PING ff02::1%eth0(ff02::1) 56 data bytes
64 bytes from fe80::6666:b3ff:fe47:e1b9: icmp_seq=1 ttl=64 time=0.032 ms
64 bytes from fe80::20d:b9ff:fe35:8849: icmp_seq=1 ttl=64 time=1.27 ms (DUP!)
64 bytes from fe80::6666:b3ff:fe47:e1b9: icmp_seq=2 ttl=64 time=0.092 ms
64 bytes from fe80::20d:b9ff:fe35:8849: icmp_seq=2 ttl=64 time=1.20 ms (DUP!)
^C
--- ff02::1%eth0 ping statistics ---
2 packets transmitted, 2 received, +2 duplicates, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 0.032/0.650/1.274/0.588 ms
jow@pc:~$
try SSH to each of the reported fe80:: IPs until you gain SSH access, make sure to append %eth0 to each address:
jow@pc:~$ ssh root@fe80::20d:b9ff:fe35:8849%eth0
BusyBox v1.24.2 () built-in shell (ash)
_________
/ /\ _ ___ ___ ___
/ LE / \ | | | __| \| __|
/ DE / \ | |__| _|| |) | _|
/________/ LE \ |____|___|___/|___| lede-project.org
\ \ DE /
\ LE \ / -----------------------------------------------------------
\ DE \ / Reboot (HEAD, r1107)
\________\/ -----------------------------------------------------------
root@LEDE:~#OK, here is terminal PrtSc...
No, you need to ping exactly ff02::1%eth0 - this is a special multicast address which pings all active IPv6 hosts in the segment. You will then get a reply from each of these hosts fe80:... addresses.
OK, some "ssh" i have 
Ouu I connected
Can I use command ??
umount /overlay && firstboot && reboot
Plain firstboot should be enough to clear settings. ( I have never unmounted overlay first.)
And command?
firstboot
Yes?
Yes. It asks confirmation, and then you do a reboot
I did it and reboot.... all without change 
...
// i find this command, it is good idea?
mtd -r erase rootfs_data
// YES its work. Thank you for all
//Please ADMIN, can you add information for other peoples?
https://lede-project.org/docs/guide-quick-start/start#coming_from_sysupgrade