I did a mistake; I wanted to try to put the LAN interface to DHCP client since I have my ISP router that runs a DHCP server.
LEDE never gets an IP and thus I can't access it anymore.
Of course I tried factory reset.
I can SSH into failsafe, but then I can't mount_root or firstboot and so after reboot it's inaccessible again
root@(none):~# mount_root
loading kmods from internal overlay
jffs2 not ready yet, using temporary tmpfs overlay
root@(none):/rom/root# umount /overlay
umount: /overlay: not mounted
root@(none):/rom/root# firstboot
This will erase all settings and remove any installed packages. Are you sure? [N/y]
y
/dev/mtdblock3 is not mounted
/dev/mtdblock3 will be erased on next mount
root@(none):/rom/root# jffs2reset
This will erase all settings and remove any installed packages. Are you sure? [N/y]
y
/dev/mtdblock3 is not mounted
/dev/mtdblock3 will be erased on next mount
if you are using a linux PC try (after booting device normally, not failsafe) $ ip neigh
then compare the MAC to that printed on the device to determine which ipv6 address to use
I've never heard of ip neigh.
I can try with a Linux PC, but can you give me some more details ? Like do I just have to connect the PC to a LAN port, do I have to assign an IP in the PC, etc ?
ip neigh is a program from a newer toolset, similar to arp
There's not much...if you're a person ...hopefully, the device is still seen via IPv6. This has been a failsafe for me before needing to open the case and use a serial connection to the board. @mbo2o then suggested if you can see its address, to use ssh to attempt access.
You may have to configure your device to ignore IPv4 and do link local IPv6; but I would attempt without making changes, first.
You looking for an entry like this on your ip neigh, bolded below:
lleachii@machine:~$ ip neigh
192.168.x.1 dev enp2s0 lladdr xx:xx:xx:xx:xx:xx REACHABLE
192.168.x.x dev enp2s0 lladdr xx:xx:xx:xx:xx:xx REACHABLE fe80::218:xxxx:xxxx:xxxx dev enp2s0 lladdr 00:xx:xx:xx:xx:xx router REACHABLE
2001:470:xxxx:xxxx::1 dev enp2s0 lladdr 00:xx:xx:xx:xx:xx router REACHABLE
Something else...if you have another router laying around, plug LAN into the other router's LAN and see if it gets an IP address. If you have a device with "Internet connection sharing" software, you may be able to access it from that machine without a router.
If LuCI is in the firmware, you should also be able to browse to the web GUI.
I finally took some time to try the stuff you suggested.
I also thought again: how is it possible that it doesn't get an IP although it's in DHCP and connected to an ISP box with DHCP server.
So I checked my ISP box and realised that I connected the LEDE router on a WAN port on my ISP box (I didn't now there were WAN ports, so I had connected the LEDE just to any ethernet port on the back).
The moral of this story is that you should never connected cables blindly
Also for others that have the same issue.
Unrelated to the initial issue, I was able to reset the router after entering failsafe mode by following this comment : Can't factory reset