Tl-wr740n Firmware Upgrade

[Agenor Ramadan]

Myfriend has a tp-link tl-wr740n router. His PC has cable connection and it's ok all the time. Unfortunately, there is a problem with wifi connection. After restarting the router he can connect to the internet with his notebook and 2 smartphones but after several minutes wifi connection stops on all devices (except cable connected PC which is fine all the time). We tried to change wifi channel, mode, and channel width and updated the firmware but it didn't help. I thought that the router is broken but our another friend has exactly the same model. He brought it and we tested it but the result was exactly the same. What could be the problem? Should we provide more information?

After a long time of successful compilation I tried to find my firmware file in /openwrt/bin/targets/ath79/tiny/ but they are not there. There are other files there but neither factory.bin nor update.bin. I read in the build guide that:

If running make does not yield images for one (or even all) of the boards linked to the device profile that you have selected, than you probably have selected/enabled too many options or packages, and the image was too big to be flashed onto your device.

I have build the images but they don't work. Router turns on and then restarts after sometime and keeps doing that. Maybe the 64MB is too low for that. I will start on an 8MB target next that many help the RAM cope better and I will have some space for additional packages afterwards. Do you have any suggestions?

as you could see, ART was on the end of flash

now, you make some 15M flash image and flashed without moving ART

it is a big chance that you already overwrite/destroyed ART partition and your device will not work

I have already saved the ART partition so even if I wrote over it , I can flash it again. Overwriting ART partition doesn't stop router from booting and getting into LUCI. My problem is that I cannot even get the router to boot into LUCI. It just keeps restarting.

Last problem is the orientation of my LAN ports. As I have a domestic Chinese router, which has small differences from the EU model, the bootloader has marked the WAN port as LAN4 and LAN1 port as WAN. I mentioned it in detail here:

-link-tl-wr740n-v5-china-flash-upgrade-issues/163660/8?u=murabat

After upgrade button click on Open-wrt firmware with factory reset done ,now router dead and When i powered up, all lights are on and off simultaneously after few seconds. I waited about 1 hour but router did not respond any ip address and does not show any connections on Network And Control center Also, I don't know what was the IP address of it.

This exactly happened to me too, when I have flashed factory firmware WITH uboot, which is wrong. Theres no way how to tell if the firmware contains uboot, except it's a bit bigger. You should have used the first released firmware, that contains no uboot I think.

This router does not have firmware recovery via tftp, so you will have to replace it, if its still in the warranty, or open the case, solder serial and recover via nokia ca42 serial cable. How to do this is in the wiki -link/tl-wr740n - see debricking.

Dear nozombian,

MY Router version 4.23 is not in warranty for now....so i want to open and case and solder serial port and recover using nokia c-42 or Dku 5 seeing this wiki link but all pictures of version 4.23 is not so clear to soldier on which port....so i need full details to recover my router..but i am not getting any useful tips to recover my router from EXPERTS too....

so i am so disappointed ...

Dear Bushrod,

I opened router case and found exactly like that on ver 4.23 pictures but picture is not so clear to be soldered ..i am sure i will fry my router if i solder any wrong wires...

i want to try with Nokia C-42 or Dku 5 cable but can't find proper guidance ,,,,please guide me..

Dear nozombian,

Thanks for useful links that i am searching for.....very thankful

Now can i connect any usb cable or Iphone data cable or

i have to use Nokia DKU-5 cable only for 3.3 v?

please guide me in simple steps because i am newbie to these steps...

I have tested only with ca 42 cable, but you can use dku 5 as well I think, for my wr741nd it is allowed to use both, wr740n and wr741nd routers are almost the same. If you have to buy one, get ca 42, if you have by hand dku 5, try it About iphone cable I have no info, but you might try google, if you have it by hand.

All you have to do to connect the router via serial cable can be seen in the video, there's not much more I can tell or describe you. You will use putty, but you will have to set it to use serial port and write port name - which one it is you will find in device manager after connecting the cable (if you are using windows), so no telnet to ip yet, have you watched the video at all? Debricking section and how to upload firmware via tftp is in the other link, just read it *carefully*, don't worry if it's for different router, most of the procedures are common, you will only have to use different firmware image, exactly the one for your router and revision.

Don't worry the theory, it's normal to be afraid of new things, but at least please read those wiki articles, there's no much sense in writing it down here with my own words, there are mostly written with far better English than I could tell you When you will have the cable ready, soldered and router communicating, you will be more clever, you'll see. When you exactly ask, what part you do not understand, there are many good people in here trying to help, but if you will not read yourself what was given to you, no one can help help you.

Openwrt is fun at the first place and fun costs money, worst what can happen is, that you will lose $17 worth your device. Many people in country where I live are working the whole day to earn that, but if you will learn, you will manage that - with a bit of skill and good luck

Dear nozombia,

Thanks for everything that you have done to me ...i really thankful to you what you have done and guided to me....

i will try all those steps and let you know about how i have done ...and the router's processing ...

Dear nozombia,

I got my Nokia Dku-5 cable and i cut off cable and found only three cables only.....now i am fully confused too ..

and also when i plugged on cable on Windows 7 laptop ,no driver of DKU5 is supporting on Device manger....USB-UART COntroller is marked as Yellow ? icon...please guide me ....

You will have to install the cable driver first, if you have windows, but don't expect me to lead you by hand, you seem to be missing elementary knowledge how do things work, so if you don't know something, try to write a question to google.com search bar first and you will see you can find some how-to for beginners.

Of course, that dku 5 is different from ca 42, so why have you bought the dku 5? You might have perfectly seen, how to do it with ca42, now you will have to find by pinout page to assign the correct pins, or you will have to find another video with dku 5 cable, if there's such. I don't have this cable, so I can't tell you which color comes where, but you should find it yourself anyway, because colors of different cable manufacturers might differ, so be sure to dissassemble the nokia pop port to see which color is connected to what pin and write it down before you will unsolder them and connect to your your router.

I connect on Com3 Speed 115200 Data 8 bits Parity None Flow Control None

but when i connect usb cable and boot router ..it response and on Putty screen commands are showing about Auto rebooting, Etho up etc as that upper link Videos ....then after 30 seconds of showing these commands My SYStem Crashes...I tried on Windows 7 and Windows XP too but same happens at last /..

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