TP-Link TL-WDR3600 (N600) v1.5 - Bricked - no cksum

I have bricked my router and I have been unable to reflash after many different attempt so I am turning to this forum in case someone might have an idea.

I am using a TP-Link TL-WDR3600 (N600) v1.5 bougth in Canada.

S/N:2148965001509

The device was running a working copy of OpenWRT and I wanted to erase my settings and start fresh. I had just finished installing DD-WRT on another device and I made a mistake where I used the resetting technique of that other device on the WDR3600 which involve pressing the reset button for over 30 sec with power on/off sequences.

I beleive the device got bricked after pushing the reset button for too long.

When powered on all the ligths flashes together indefinetely.

The recovery seems to be working, it is asking for file "wdr3600v1_tp_recovery.bin".

I am using a TFTP server on Arch Linux on my host and all packages are up-to-date.

I also disabled the firewall.

When the router gain access to the file I get a bunch of lines like those and the the lights blink back again, it doesn't look like the file gets transferred successfully:

04:15:45.776027 IP (tos 0x0, ttl 255, id 16, offset 0, flags [DF], proto UDP (17), length 72)
192.168.0.86.2960 > 192.168.0.66.69: [no cksum]  44 RRQ "wdr3600v1_tp_recovery.bin" octet timeout 5
04:15:45.780529 IP (tos 0x0, ttl 64, id 52518, offset 0, flags [none], proto UDP (17), length 40)
192.168.0.66.40439 > 192.168.0.86.2960: [udp sum ok] UDP, length 12
04:15:45.780615 IP (tos 0x0, ttl 255, id 17, offset 0, flags [DF], proto UDP (17), length 32)
192.168.0.86.2960 > 192.168.0.66.40439: [no cksum] UDP, length 4
04:15:45.780707 IP (tos 0x0, ttl 64, id 52519, offset 0, flags [none], proto UDP (17), length 544)
192.168.0.66.40439 > 192.168.0.86.2960: [udp sum ok] UDP, length 516
04:15:45.780806 IP (tos 0x0, ttl 255, id 18, offset 0, flags [DF], proto UDP (17), length 32)
192.168.0.86.2960 > 192.168.0.66.40439: [no cksum] UDP, length 4
04:15:45.780864 IP (tos 0x0, ttl 64, id 52520, offset 0, flags [none], proto UDP (17), length 544)    
192.168.0.66.40439 > 192.168.0.86.2960: [udp sum ok] UDP, length 516
04:15:45.780971 IP (tos 0x0, ttl 255, id 19, offset 0, flags [DF], proto UDP (17), length 32)
192.168.0.86.2960 > 192.168.0.66.40439: [no cksum] UDP, length 4
04:15:45.781100 IP (tos 0x0, ttl 64, id 52521, offset 0, flags [none], proto UDP (17),
length 544)

I have tried most version of OpenWRT images, the original stock firmware, stipping down characters, etc.

There is no need to list them all, there seems to be another problem.

Any suggestion would be great, I really love this router, it has 2 atheros anthenas.

Thank you for reading me.

Try an alternative machine for your tftp server & work only with stock roms.

The tl-wdr3600 can be recovered via tftp just fine with the OpenWrt factory images; personally I prefer tftpd-hpa for that purpose, but any tftpd should do.

1 Like

I have been trying to fix my router, tftp upload seems to be successful but I do not see any array of lights indicating that there is a flashing process going on. Is there anything that I am missing ?

You can check if the tftp transfer completed by ramping up the logging on the tftpd part and/ or using wireshark/ tcpdump to check what actually happens on the wire. Even after a complete transfer, it's still possible that the bootloader rejects the received firmware (incorrect hardware ID, incorrect region code, etc.), once you hit this, serial console access would be the next step - as that usually uncovers the error messages from the bootloader (and may give you hints why the bootloader rejects your firmware).

thanks for the update. Since I do not have a serial with me right now, so using the router as a switch(which was the purpose anyway). From what I read online it looks like the bootloader got erased/corrupted (as per a post in the ddwrt forum) and the router is rejecting the firmware after successful TFTP upload. I will hook it up with the serial and write the firmware directly if possible.