Tl-wr740n Tl-wr740nd Firmware

[Valda Atkeson]

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?

1) This device does not have sufficient resources (flash and/or RAM) to provide secure and reliable operation.

This means that even setting a password or changing simple network settings might not be possible any more, rendering the device effectively useless. See OpenWrt on 4/32 devices what you can do now.

The serial headers are not completely connected (a voltage divider and capacitor are left out, so the headers are dead), but a serial connection can still be established by soldering directly to two of the empty pads. The result is a bit unstable (router output is often partially lost) and can probably be improved electrically.

The v4.23 uses the standard TP-Link pinout, however the TX pin is not connected to the CPU. In order to make the TX line working, the two points on the bottom side of the PCB must be connected with a small wire. The pin at the SOC is labeled TP18, the one at the serial connector is labeled TP28. The RX line is 5V intolerant! So the connection needs a 3.3V RS232 level shifter. Pins on the connector on the photo are TX-RX-GND-3V3(VCC) (from left to right).

At the original time of writing, no method was known to recover most models from a bad firmware without soldering the serial cable. However, ongoing experiments suggest that TFTP flashing is possible even without soldering a serial port. The list of models and versions which have a factory U-Boot compiled with tftp enabled is to be determined. It's best to try it yourself because there's nothing to lose, but please do share your results at the respective wiki page. For more information, see: -secret-of-tl-wr740n-uncovered.html

Forum member pepe2k made a modification of U-Boot 1.1.4 for Qualcomm Atheros SoCs based devices (the project is still being developed, so new devices and SoCs will be supported in the future). Up to date information, binary images and sources can be found on official GitHub repository.

This modification started from wr703n-uboot-with-web-failsafe project, but supports more devices, all modern web browsers, has a lot of improvements and other modifications (like U-Boot NetConsole, custom commands, overclocking possibilities etc.).

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