[SOLVED] Trying to recover bricked Fritz!BOX 7530

Hi everyone,

I've fouled up and very bricked my much loved Fritz!BOX 7530 (https://openwrt.org/toh/avm/avm_fritz_box_7530) and so far not having much luck recovering it. Posting in the hope someone can assist?

Source of the problem was a messed up customized firmware, which lacked critical components such as procd. This means it certainly can't boot or get an IP address.

Here's what I tried:

AVM recovery tool

AVM Recovery Tool. I've got a Windows machine and tried it. However, I'm failing to see how this tool can work; the box is so bricked that it can't get an IP address, so in spite of trying a few combinations of subnets:

  • 192.168.178.x (the box default)
  • 192.168.2.x (the subnet I was previously using)
  • 192.168.1.x (not using it, but who knows?)

The box doesn't respond, so can't go further.

uboot

As per the installation instructions at https://openwrt.org/toh/avm/avm_fritz_box_7530#installation which I used long ago. It seems like I can successfully transfer uboot:

$ /usr/bin/python3 ./eva_ramboot.py --offset 0x85000000 192.168.178.1 uboot-fritz7530.bin
> SETENV memsize 0x00080000
< 200 SETENV command successful
> SETENV kernel_args_tmp mtdram1=0x85000000,0x88000000
< 200 SETENV command successful
> MEDIA SDRAM
< 200 Media set to MEDIA_SDRAM

However, then when moving on to try tftp flashing, I have no luck; trying some GUI options for macOS such as Intuitibits Transfer or Trivial.app, I see no evidence of the device trying to pull the image.

So the question here is, is the eva_ramboot output above actually success? If so I could persevere with tftp.

Other than that, any ideas? It would be a pity to abandon this device since it's served me so well. However, on the other hand it's getting a little old so it wouldn't kill me to use this as a chance to upgrade.

Hope someone can help!!

Thanks in advance

For the recovery tool it shouldn't matter, it talks to the modem before it tries to boot your bricked firmware. I'd definitely make sure it's not a problem with your ethernet/windows setup first. The recovery tool works with Linux and wine, you technically don't need windows, at least it has for me in the past.

That said perhaps it's not working as per : https://openwrt.org/docs/guide-user/installation/recovery_methods/avm_recovery_tool

See point 4 a (ignore the rest) then Fritzbox 4040 flash: FTP connection refused - #4 by JevermeisteR

I think there's better info out there somewhere on the forum but I remember I got the recovery tool working once by using what JevermeisteR says there.

If you definitely confirm no attempt to grab the file, perhaps there's a problem with the uboot file, where are you getting it from ?

There's one I made a few changes to and compiled separate from openwrt when I was having trouble trying to get past a badblocks problem here https://disk.yandex.com/d/4js74QAjB2PkzQ i'm pretty sure it works but yeah. I don't think it will do any harm since all it does it load it into memory when you run that command it doesn't write anything to flash. If you find that it does work when the other one didn't maybe you should look for a different source for the uboot file when it comes time to actually write one on if you need to.

Thanks for your input @wilsonyan. I'll read further through those links and try again later

Will just mention one more thing just incase, for the uboot, make sure you actually have the tftp server set to ip 192.168.1.70 exactly. Maybe that's why you're not seeing the request.

^ Yes, I did follow the IP address instructions to the letter. In any case, will have another try later and report back. Thanks!

Ok! Happy to report that I was able to use AVM recovery quite simply with just:

  • IP address 192.168.178.10 (https://openwrt.org/toh/avm/avm_fritz_box_7530#installation)
  • Ran the tool on Windows as admin, and gave all rights it asked for
  • Run tool, found no probs, had to remove my USB card first, second time round it appears to be completing successfully
  • Stock AVM firmware wlan pops up and available at http://192.168.178.1/ (haven't seen that thing for a while!)

Now to reflash OpenWRT and not screw it up this time :laughing:

Thanks for your support and necessary encouragement @wilsonyan

U-Boot is configured to only boot via TFTP as a fallback: https://github.com/chunkeey/FritzBox-4040-UBOOT/blob/48430dfa5b0d72e81eb51b044ee5d2c2eee468c6/include/configs/fritz7530.h#L18-L26

If there is already an OpenWrt image on the device, it will always boot that. To get it to use TFTP again, it is necessary to either remove OpenWrt (which you did using the recovery tool), or build a custom version of U-Boot.

2 Likes

Ok, now reporting back after finally succeeding in reinstalling OpenWRT.

The problem I was having was uploading the uboot image, which I didn't have the first time I flashed from the stock firmware. The key was indeed to using the PeterPawn scripts. Indeed it seems to be that EVA is not available after AVM recovery and intervention is required. Needed to use the Powershell version on the Windows laptop I was previously using for AVM recovery, since macOS isn't compatible enough with the Linux script for this kind of networking. After that I had an IP address to upload uboot and continue install as normally.

Since I got into this mess by (in my opinion) the firmware selector making this too easily done, made an issue over there to protect the user a little more: https://github.com/openwrt/firmware-selector-openwrt-org/issues/47