If you cannot access the LUCI OpenWRT page of the TP Link WDR4300 router, the below may help.
- Set PC ip: 192.168.1.2 and subnetmask 255.255.255.0 and gateway 192.168.1.1
- Power off the router
- Disconnect the WAN cable
- Only connect your PC Ethernet cable to ETH0
- Power On the router
- Wait for the router to start the boot sequence (SYS LED starts blinking)
- When SYS LED is blinking, hit restart button (When SYS LED blinks at faster rate, the router is in fail safe Mode)
- Open a terminal window on the PC.
Immediately, type below command and hit enter button while the SYS LED blinks rapidly:
$ telnet 192.168.1.1 <enter>
Note I typed
$ ssh firstname.lastname@example.org <enter>
Run these commands in the router window.
# mount_root <enter>
This remounts router partitions from read-only to read/write mode.
# firstboot <enter>
This will reset the router after reboot.
# reboot -f <enter>
This will force reboot.
Now login to the web interface using web browser.