[Gelöst] Update Firmware 6490 kdg branded to 6.83 Article Number 20002691 (English post)

Dear Folks,
First I would like to excuse because I am writing in English, I hope it is not against the forum rules.

My intent is to demonstrate how I could update my Fritzbox 6490 KDG branded to firmware 6.83.

It was quite challenge to me because I am not German speaker and almost all material are in German. I also would like to summarize all my steps and trick steps that I passed in order to help others with the same issues I passed.

I thank all the information that were provided in the forum especially to lleeaaddeerr, fesc and PeterPawn posts which gave the main information that I need to proceed.

One of my difficulties was to follow all the 1900 posts in the thread http://www.ip-phone-forum.de/showthread.php?t=286994, which was the main source of the process described below.

My case: I have bought in ebay for 40 Euros a Fritzbox 6490 articlenumber 20002691, I knew that I might have problems to use and update but because the price I decide to take the risk.
My device was KDG branded and with firmware 6.26. I would like to use it on KMS (cablesurf Munich)

Lets see what I did:
First I have De-branded (easy part):

1. Connect the device in the Lan1 port with an Ethernet cable directly to your computer;
2. In the windows execute console write FTP 192.168.178.1 (do not press enter yet);
3. Turn of the Fritzbox 6490, after 3 seconds (few time), turn on again. All leds will blink once than the Power/cable will start to blink alone. Now you press enter in the windows console.
4. The FTP screen will appear asking the username adam2, press enter
5. Password adam2, press enter. You are now connected
6. So input the following commands:
   1. quote GETENV firmware_version (this is optional, and it is only to see which version you have, mine was kdg)
   2. quote SETENV firmware_version avm
   3. bye

So now you have de-branded the firmware to avm, however it still not possible to do web upgrade in the firmware.

After these steps I was trying to follow other procedures to be able to update the firmware, including the one I will explain below, but it only works after some process which I really do not know if it was to be like that. So I will explain what I did and might work to you also. Remember I am really just a curious person with no big knowledge of programing or hacking.

So after all not success upgrades I have decided to activate the my modem in KMS (cablesurf Munich) even with the old firmware. Until that I was connected in Internet with my older modem and Fritbox connected to my computer by the Lan1 port.

Fingers crossed, KMS (cablesurf Munich) had activate without problems and I start to surf by my new Fritzbox with old firmware. Then I decided to configure my voip telephone number, however the button to add a new number was not appearing in the manage telephone number in the firmware menu.

After some search I was believing that the solution was to make a factory reset. I was concern to do it because read that someone has problems of bootloop after factory reset, but I decide to try. After that I could configure my telephone number flawless.

I was thinking, as the telephone was a particular issue maybe the failure in updates could be the same, so I decide to make it again. However my scenario was different from the previous tries.

So I would include this steps as part of the procedure but I could be wrong if it really matters.

1. Activate the modem in your provider, and connect internet through it.
2. Disconnect the Lan1 from computer and connect by WIFI (all my failures was connected by Lan1)
3. Make a factory reset in the modem (Go in the firmware menu – 192.168.178.1 - System / Backup / Factory settings

An now you can start the procedure to update the firmware with the trick of the Developer tools of your browser.

1. Download the firmware image from: http://download.avm.de/firmware/6490/35717120/FRITZ.Box_6490_Cable.de-en-es-it-fr-pl.141.06.61.image
2. Connect to Firmware page 192.168.178.1
3. Navigate in the menu to System / Backup / Restore tab
4. Click with the right button of the mouse over the button Choose file, than select in the menu Inspect element.
5. A Developer frames will open with the source codes of the page. You will need to change the following information:
   1. <input type="file" id="uiImport" name="ConfigImportFile" size="40"> Change it to:
   2. <input type="file" id="uiFile" name="UploadFile" size="40">
6. After this change in the source code, just click in the Choose file button (normal button of the mouse) and select the Firmware image file that you had download in the step 1.
7. Click now Restore button.
8. If it works for you, the file will be upload to the modem and then the update starts. It take time, around 5 -7 minutes. Wait with patience and do not turn off the modem.
9. If it not works, you will see a message similar to an Unspecified error occurred during the update. (0)…

If you were successful your firmware is now 6.61 with no brand, and you can now update directly to the newest firmware 6.83 (this in Jun 2017).
To do that you follow the same procedure as an owner of an articlenumber 20002778 device which is:

1. Connect to Firmware page 192.168.178.1
2. Navigate in the menu to System / Update and press Find New FRITZ!OS button.

These were all I did and now I have my 40 euro device doing the same as the 189 Euro articlenumber 20002778, I hope I could help others like me.
It might not work with higher firmwares, and I know some people needs to have telnet access to update in the flash memory directly. Unfortunately I could not follow this kind of process, so I am very happy that I could do it in this way described above.

Good luck to you folks.