An old battle; Cisco 877 with BT ADSL2+

Last week I had the missfortune of needing to get some low bandwidth endpoints online for a client, these unmanned locations would have a few peices of technology sat behind an ADSL router with an IPSEC VPN back to a central location,bog standard stuff!

Naturally, I’d specified Cisco 877 ISR routers (as anything newer was overkill) allowing a good level of remote management, monitoring and control.

Base configuration was written offline, router is then connected to a BT ADSL2+ socket and an issue I immediatley recognised reared it’s ugly head;

Errors would repeat every 30 seconds to 5 minutes, nearly two years on, 877’s still don’t support BT’s ADSL2+ connections it seemed!

Expecting a new, working ADSL firmware update in that timeframe, I headed to the website and was bitterly dissapointed, even the firmware release ‘patch’ of yesteryear had been removed (which we didn’t have much luck with anyway when it first came out).

I knew we were looking for at least (or 4.0.18 depending on where you see it written), backed up by many sources (just search for ADSL2+ BT Cisco 877).

What’s clear however, is that as talked about all over the place doesn’t seem to be solving anyones problems and after getting hold of a copy by searching google for the what the filename would be based on the download ( ) I once again confirmed this, even setting the line type to only ADSL2+ to rule out any negotiation issues still saw consistent drops every minute or so;

conf t
int atm0
dsl operating-mode adsl2+

(At this point it is probably worth mentioning that the 877 will use new firmware as long as it is called ‘adsl_alc_20190.bin’ and is found in the routers flash on startup (if not, the default firmware in the IOS will be used), further details and screensots courtesy of here!)

Eventually, after a lot of firmware testing, I found that cisco have some ‘by request’ only firmware versions which not many people seem to know about.
After testing internal version 4.0.223, I can confirm that my ADSL2+ link suddenly became stable and has continued this way ever since (Now over one week).

I think it’s a little strange that Cisco has kept this one so tightly under wraps.
Anyway, I am not suggesting that this firmware is fit, safe or even sensible to use, but it has resolved my issues here and if you’re reading this and at the very end of your patience with an 877/ADSL2+ combination, you can find the firmware at the link below;

I hope this helps! Let me know if you have sucess with this, would be interested to see how many people are still affected.

8 thoughts on “An old battle; Cisco 877 with BT ADSL2+”

  1. Thanks for that link! That firmware seems to be working great, much less errors than previous versions. I havent been transfered to adsl2 yet but I wanted to get it ready incase there were problems on the switchover, but its working better already.

    1. Hi Stuart,
      These are running on; C870 Software (C870-ADVSECURITYK9-M), Version 12.4(24)T5.
      However, I’m sure I’ve also used this on 15.0 IPSERVICES (though I’m having trouble remembering where to verify that).
      Hope this helps,

  2. Hi Matt.
    Thanks for this. Have you tried the 0.0.26 version that is now available on the Cisco site?
    Once loaded this reports in “sh dsl int a0” as:
    Init FW: init_AMR-5.0.007.bin
    Operation FW: AMR-E-0.0.026.bin
    FW Source: external
    FW Version: 0.0.26
    This seems to have helped the stability for me at a site.

  3. Yo!

    I can confirm we have this running on the latest 15.1 IOS and it resolves similar problems, it also resolves a few issues on non ADSL2+ connections as wells such as random disconnects so ideal to upgrade even if you don’t have ADSL2+.


  4. Thanks for the post. On Cisco’s website there is now an adsl_alc_20190_0.0.026.bin firmware available. Although the filename indicates this would be a really old version the date seems recent (November 2011).

    Can anyone indicate whether this is more or less recent (and stable) than the 4.0.223 you’ve mentioned here?

    Here’s an output with the 0.0.026 firmware…

    Router#sh dsl int
    Alcatel 20190 chipset information

    Line has not yet been activated.

    Modem Status: Down (DMTDSL_STOP)
    DSL Mode: Unknown
    Interrupts: 4142 (0 spurious)
    PHY Access Err: 0
    Activations: 0
    LED Status: OFF
    LED On Time: 500
    LED Off Time: 500
    Init FW: init_AMR-5.0.007.bin
    Operation FW: AMR-E-0.0.026.bin
    FW Source: external

  5. Just in case anyone still comes across this …
    877 is not recommended for use with ADSL2+ due to the very old STM modem, but if you do want to use it with BT ADSL2+ then the recommended stable firmware is the 0.0.026 release developed specifically for this purpose.

  6. THanks. 4.0.223 works well. My 877W now actually syncs at ADSL2+.

    sh dsl int
    Init FW: init_AMR_4.0.223.bin
    Operation FW: AMR-E-4.0.223.bin
    FW Source: external
    FW Version: 4.0.223

    Speeds are syncing faster already.
    sh dsl int atm0 | i Speed
    Speed (kbps): 0 8403 0 964

    Might try the 0.0.026 later…

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