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[HELP] Router DD-RWT dirty flash
Hello there
I was upgrading my wr940nv1 but accidentally downloaded wr941nd ddwrt file and now the router is in bootloop
I really have no experience in setting up serial connection ...
On YouTube people have been able to flash router firmware without serial connection using tftp server
I tried the tftp method But this doesn't work at my end :-(
Any suggestions
Thanx in advance
Comments
Have you tried contacting the youtubers?
either set up a serial connection or recycle it in your local bestbuy,etc.
I think you're better helped by asking in the ddwrt forum
Read your router manuals to find if it have some recovery/failsafe/emergency procedure to allow upload a recovery firmware image. I recall D-Link ones have this but (I used it in the past) not sure about TP-link.
To be clear it's easy to recover with tftp server, I have several times repaired mostly dead routers. Google for tftp wr940nv1. It's super easy. Whole logic in next: router has some mode which allow you to automatically upload router image to the rounter after pressing and holding power button (or reset, depends on the router) and emulating tftp server and client, and rounter will automatically when boot catch the ISO and will install it. Than it will install it. And for future: NEVER EVER UPGRADE ANY FIRMWARE FLASH, tplinks very bad routers in this terms.
tftp is the best method google for your device or "tp-link tftp" you can run a server on your windows or linux machine then it's just a case of setting the right ip's and filename. Then normally you hold the reset button in and power or on (or something similar) to put in tftp mode.
I have updated firmware many times
I guess my luck ran out
Check https://openwrt.org/toh/tp-link/tl-wr940n
TFTP should work. Some of my usual mistakes include
Maybe a 30-30-30 reset will help
How do you put TFTP server in binary mode
using win 10 and tftpd64 by Ph.Jounin
Easiest way to flash it is connecting via serial, as you can see exactly what is going on
tftpd64 might use binary mode automatically. I have only used Linux
tftp
.BTW, Are you sure you are booting router into recovery mode? Pull out the plug, and with the "reset" button pressed plug it back in. Wait for 5 to 15 seconds and the LEDs will start blinking or you might hear a beep. Then release the "reset" button. Also make sure ethernet cable from PC is plugged on a LAN port of router, and not the WAN port. With your IP address set to 192.168.0.x ping the router on 192.168.0.1. If that works, then TFTP transfer should also go through.
https://forum.tp-link.com/showthread.php?81462-How-to-recovery-the-router-when-you-bricked-it
Follow and adapt it to your router. Not that hard, and fixes the damned thing. Then put it back in the box and get a real router. TP-Link has gone to shitballs lately.
My country is in lockdown and I can't get to the nearest electronic shop to get USB UART
Otherwise it would have been easy
I have couple of users and most of the devices are n only only I have one 5ghz device (but not ac) and only one AC ....
Upgrading router is not justified . obviously if i couldn't recover it then that would be the way to go :-)
Download: from Mega whole archive with image and tool what you need to use
Connect to your router via LAN cable and your ethernet adapter on laptop or PC
Just screenshots
Update
Router Fixed finally
Few things if anyone stumbles upon this thread
WR940NV1 or WR941NDV4
Easy Method
TFTP Server via Recovery Method
Methods mentioned above simply doesnt work in this model
Little Difficult Method
You need to solder headers to RX TX and GRND and use a USB to 3,3V Serial Adapter
Note the serial port on the right part of the board, approx. in the middle. Four pins next to the two large capacitors.
The serial port pinout is TX, RX, GND, NC. (in the picture from bottom to top)
you can always use a Digital Multi meter to verify this
Use this layout
USB <--> Router Board
RX <--> TX
TX <--> RX
GRND <--> GRND
Next Step
use Putty and Setup this as follows
Com Port : accordingly
Baud Rate 115200
Data bits 8
Stop bits 1
parity none
flow control none
Next power up the router and login in..
if you have done everything write you should start seeing U boot interface
if not
check if pins are soldered properly and usb to uart ttl drivers are correctly installed
Now the router is in boot loop and will give you only 1 sec to stop it
You have to type "tlp" and it will stop
Note: on some models you can use Ctrl + C
This can be annoying some time as you have to get this right
Next Step is simple
type "printenv"
it will give you server ip and its own Ip address
for WR940NV1 The parameter values are
ipaddr=192.168.1.123
serverip=192.168.1.100
bootargs=console=ttyS0,115200 root=31:02 rootfstype=jffs2 init=/sbin/init mtdparts=ar7240-nor0:256k(u-boot),64k(u-boot-env),2752k(rootfs),896k(uImage),64k(NVRAM),64k(ART)
bootcmd=bootm 0x9f020000
bootdelay=1
Now you need to connect it to a computer using the prefferably eth0 i.e the first lan port
Setup static Ip the value of serverip will be yourcomputer ip and the parameter ipaddr will be your gateway
subnet mask is simple 255.255.255.0
Now you have to setup tftp by Ph.jounin
Open tftpd on your computer
select the correct interface
select the directory with the downloaded firmware from tp link website.
Rename the file to firmware.bin
Next switch back to putty and type this command
tftpboot 0x80000000 firmware.bin
Now if you have done everything correctly the file will be uploaded.
Now it will give you a file size of file uploaded in Hex
This is important !!! Save it
Next Step is to get the correct hex address for flashing
type printenv bootcmd
bootcmd=bootm 0x9f020000
the address in hex will give you the address
Next Command is this
erase.b 0x9f020000 +0x3c0000
The first parameter is the hex address and the secondparameter after + sign is the filesize
if you enter incorrect hex value or file size the router will be again in bootloop
next step is copying the flash
type
cp.b 0x80000000 0x9f020000 0x3c0000
again adjust parameter according to your values
if all these commands didnt gave you an error you are ready to test your router
you dont need to disconnect the router a better way is to type this command
bootm 0x9f020000
again adjust the value accordingly
if the flashing was correct you should start seeing the router booting up properly.Also look at the router leds
if the flashing was incorrect then the router would be again in bootloop
This means the three important commands
tftpboot 0x80000000 firmware.bin
erase.b 0x9f020000 +0x3c0000
cp.b 0x80000000 0x9f020000 0x3c0000
you made a mistake of hex value
or the firmware you are flashing again is corrupt
This is just a rough guide written in 10 -15 mins
It's tpl not tlp
That was an impressive read. I would have taken the easy route (pun intended and just went and bought another one.
Good job with this one. I keep a handful of USBTTLs (PL2303HX to ya motha) around for just these sort of projects.
Oops
Very nice thread. Although a little complicated, serial connection is always helpful.