Hello everyone, but I broke a router I have a couple of queries. I have a TP-LINK 841N that was manufactured for a specific ISP Telecentre (Argentina). Stop us there. Is not it just that tp-link only manufactures routers for special uses and no particular company ?. Two, however much it is made for that company, the router is mine and therefore I can do whatever I feel like. I wanted to flash it with dd wrt and I bricked it. Then I put stock firmware and openwrt but it never worked again. Is it not that in the 841N hardware all have to be identical? But I should carry another model. That changed in the hardware so that the other firmwares do not work ?. If anyone has the original Telecentre firmware for these routers I would appreciate it. Try to flash all possible firmware with a programmer for SPI memory but nothing went. Thank you for reading this post

(Last edited by pindonga123 on 8 Aug 2017, 00:13)

Hey there.

As of this wiki page, the 841N is identical to the 841ND except for the detachable antennas:
https://wiki.openwrt.org/toh/tp-link/tl-wr841n

As of this wiki page, there are 13 different revisions of the 841ND, all of them require different images:
https://wiki.openwrt.org/toh/tp-link/tl-wr841nd

You might just have picked the wrong image and if you find the correct one, your router might start working again.

But since there's obviously lots of different versions of that low budget device, to me it's not entirely impossible there's another revision not being sold direct to customers but only to ISPs.
Usually special ISP models are internally identical and only have special casing (see e.g. german AVM fritz box for german ISP "1&1", they have grey and black boxes compared to the regular red ones AVM usually has) and some restrictions in terms of software. But chances are there's some ISP devices out there that differ not only in terms of color and software but in terms of chip layout as well.

Regards,
Stephan.

(Last edited by golialive on 8 Aug 2017, 09:47)

If it's simply a re-badged 841, you may find the version number on a sticker on the circuit board inside even though the ISP put their own label on the outside.

Does the bootloader still work?  Have you tried a serial console?  Almost all the Atheros based TP-Links have the same flash layout-- bootloader first 128K, ART last 64K, firmware in the middle.  You can use a flash writer to drop an OpenWrt "sysupgrade" bin image directly into the chip at offset 128K.

A truly custom version might be like the Chinese market versions which have only 8M or 16M RAM instead of 32.  In that case you are out of luck.

(Last edited by mk24 on 8 Aug 2017, 14:24)

It does not work in the end. Flashed this bin downloads.openwrt.org/chaos_calmer/15.05.1/ar71xx/generic/openwrt-15.05.1-ar71xx-generic-tl-wr841n-v8-squashfs-factory.bin. My version is 8.0, after I tried with this TL-WR841ND-V8-stripped.zip and after with the original firmware downloaded from Tp-Link site and in the dd-wrt site. Nothing happened. The router show Power LED, The LED that is like a world with a ring in the top, LAN 1,2 and 3 LED all they turn on always and nothing happened. Sorry but my english is not good. I tried to set 30-30-30 hard reset but the reset buttom doesnt work. Please help me. I have a doubt the SPI programmer doesnt program the bootloader?. Only the firmware. There is the confusion

(Last edited by pindonga123 on 9 Aug 2017, 12:56)

Do you get anything on the serial console?  If you don't see the bootloader starting, you probably need to replace the bootloader.  Get a factory firmware that includes the bootloader (has 'boot' in the name) and remove I think the first 512 bytes, then flash starting at offset 0 in the chip.

An SPI programmer can write to all areas of the chip, so you have to be careful.  In particular don't overwrite the ART partition at the last 64k.

Another approach would be to get another router of the same model and copy the bootloader and firmware out of its flash.

I have a SPI programmer, I´ve never used serial port, never understood how use it, tried to learn but I couldnt. So I decided buy a SPI programmer, so I downloaded the firm and flashed with it. So Did I broke my router?

You have probably overwritten the bootloader by placing the firmware in the wrong place in the flash chip.

First thing you should do is read the whole chip and store that as a backup, hopefully the ART is still OK.  The ART data is unit-specific written at the factory with things like the MAC address and radio calibration.