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Customer Review

on March 1, 2013
*** [...] ***

This is an update to my initial review. There *is* a problem with the BLACK SB6141 modems, but it's not what I originally thought.

The BLACK modems are older than the WHITE modems, and ship with an older firmware version that had a serious bug (v1.0.6.3). If you are a TWC customer, BEWARE. As of February 2013, it was TWC policy to NEVER update the firmware of customer-owned modems. I don't know the policy today or the policy in other areas, but if your ISP will not update the firmware of any customer-owned modems (or won't update the SB6141, specifically), do not buy this modem!

** Confirm with your ISP that they will update the firmware before buying this modem. ***

My initial review repeated what a Motorola tech support person told me - that my modem was defective (constantly "flapping" - dropping the connection) because it was fraudulently sold to me as new when it had to be used - had to be used because it was black, and not the version intended for consumers. The black modems are non-retail - sold by Motorola only to ISPs. The white modems are the ones meant to be sold directly to consumers. He knew there were a lot of problems with the black modems because he was fielding so many phone calls, but he guessed wrong about the reason for the problems. Apparently, the BLACK modems ARE being sold new to consumers by unauthorized sellers (and thus are not under warranty!). However, they have older defective firmware on them, and the only party that can legally update the firmware per DOCSIS 3 is the ISP. Some ISPs - notably, TWC - refuse to do this as a matter of policy. Others, like Mediacom, don't support this specific modem.

ALSO NOTE: The BLACK modems are NOT UNDER WARRANTY from Motorola because they were not intended for the retail stream. Only modems purchased from authorized sellers are under warranty, and authorized sellers only sell the WHITE modem.

--------------------------

The comments to this review contain endless arguments, mostly about whether the BLACK modems are new or used. The most recent comments challenge whether there really was a firmware bug. For the sake of the innocents who come by and read this review, here is the documentation.

And by the way, the reason I know all this is because I was bit by this bug - BAD. I bought my own cable modem (a black SB6141) as soon as I could, and then the nightmare began. Everything you are about to read is stuff I learned on my own because TWC was of no earthly use at all. I work out of my home and critically need internet. TWC wasted months of my time and cost me thousands of dollars without ever finding the answer. I found the answer myself. No one at TWC even knew about the firmware bug.

--------------------------

NOTE: Amazon is probably going to remove all the links from this review (though they are very useful and don't link to products). If you want to see them, look at page 23 in the comments.

--------------------------

The link below is to a scan of the Motorola firmware update documentation, listing the defects fixed in firmware version 1.0.6.8. Firmware v1.0.6.8 is what the WHITE modem ships with. The BLACK modem ships with an older version of the firmware, v1.0.6.3.

[...]

Motorola added one "new feature" (optimized performance a bit better) and fixed several things, but here is the critical bug (and I quote):

-----------------------

8.1.2 Defects Fixed

- A random connectivity issue caused by T3/T4 timeouts when operating in Upstream Channel Bonded (USCB) mode has been resolved. Previously, the SBCM would stop ranging on an upstream after a RNG-RSP ABORT is received from the CMTS for one of the upstream bonded channels, causing the unit to reset. Now the unit will not reset, but continue operating in Upstream Partial Service Mode, utilizing upstream channels that fall within the allowable DOCSIS upstream transmit power ranges. (SB-2790, SB-2643, SB-2638)

-----------------------

In English: Because of a firmware bug, the modem was over-sensitive to any kind of line problem, and lost the connection completely when a problem was encountered. The firmware update corrects this. Now, if one channel is out of range, the modem ignores that channel and uses the channels that remain in-range - i.e., the modem maintains a partial (slower) connection instead of dropping the connection completely.

You can see from my modem log (which I saved) that the horrible "flapping" problem I experienced (constantly dropped connections - sometimes every few minutes) was caused by this bug. Look at the excerpt below. See how the T3 and T4 timeouts are causing "critical errors" (lost connection)?

-----------------------

Feb 22 2013 15:44:31 5-Warning T202.0 Lost MDD Timeout;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 15:44:09 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 15:37:30 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Jan 01 1970 00:00:14 6-Notice Cable Modem Reboot due to T4 timeout ;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 15:34:21 3-Critical R04.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 15:32:57 5-Warning T202.0 Lost MDD Timeout;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 15:32:34 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 15:02:30 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Jan 01 1970 00:00:14 6-Notice Cable Modem Reboot due to T4 timeout ;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 14:59:58 3-Critical R04.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 14:58:23 5-Warning T202.0 Lost MDD Timeout;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 14:57:59 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 22 2013 12:57:16 6-Notice D106.0 DHCP Renew - lease parameters time server-24.29.158.48;tftp file-?BBgdiSyUzLlFew0KMW7Z@CjFu2VTmP4thsTV83CGcYVp2JONZj0g3 modified;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 18 2013 10:37:25 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 18 2013 09:21:43 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Jan 01 1970 00:00:14 6-Notice Cable Modem Reboot due to power reset ;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

Feb 17 2013 22:31:28 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 12 2013 16:32:29 6-Notice D106.0 DHCP Renew - lease parameters time server-24.29.158.48;tftp file-?BBgdiSyUzLlFew0KMW7Z@CjFu2U1F_xuMzGcv41OSB7zwsiEVTiiI modified;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

Feb 12 2013 09:21:10 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=94:cc:b9:45:7b:0d;CMTS-MAC=00:21:55:cb:62:b0;CM-QOS=1.1;CM-VER=3.0;

----------------------

Motorola released another firmware version shortly after the big fix - v1.0.6.10. At the time I gave up on the modem (since TWC would not update the firmware on customer-owned modems), this was the current release. I think it still is. Here's a link to a scan of the release notes for that version (see page 23 in the comments if Amazon deletes it):

[...]

If you read the "Defects Fixed" section, you'll see more corrections to timing issues - but the big problem was fixed in v1.0.6.8, which is what ships with the WHITE modem (the retail version).

I'm now using a TWC-owned modem because of their adamant refusal to update the firmware on customer-owned modems. I still have plenty of errors in my modem log, but this modem (with its non-buggy firmware) recovers gracefully from the crappy lines and equipment around here.

*************** BOTTOM LINE!!! ***************

CONFIRM WITH YOUR ISP THAT THEY WILL UPDATE THE FIRMWARE OF CUSTOMER-OWNED MODEMS - AND THE SB6141 SPECIFICALLY - BEFORE BUYING THIS MODEM. IF THEY WILL NOT, DO NOT BUY THIS MODEM!! AS IS, IT IS FAULTY.

THE WHITE MODEM HAS A LATER VERSION OF THE FIRMWARE - THE ONE THAT FIXES THE DEADLY "DROPPED CONNECTIONS" BUG. IF YOU WANT TO BE SAFE (NO MAJOR FIRMWARE BUGS AND A MODEM UNDER WARRANTY), BUY THAT ONE.
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