MB-8611 Motorola modem fails to reconnect after an Xfinity server software reboot.

To:  Xfinity software Support – Network Systems

Date: 6/2/2026

Customer:           Lake Jackson, Texas USA   77566

 

Xfinity Account #:  *****************

MB-8611 modem MAC address:  ******    DOCSIS 1.1 Cable modem

Modem installed new:  04/06/2023

 

Subject:  MB-8611 Motorola modem fails to restart after an Xfinity software reboot.

This problem started on March 1, 2026 and has continued for the last 3 months.  On selected nights, Xfinity is taking a software restart (or reboot) on their servers at 2:00 AM Central Time. It is always at the same time each night.  Sometimes a 2nd reboot occurs after 3:00 AM Central Time.  Our modem does not have any problems during other hours of operation.  No problems were occurring before 3/1/2026.

The symptoms are:

Our MB-8611 Motorola modem (which is on the approved Xfinity list) fails to automatically reconnect after an Xfinity outage.  If we call Xfinity Desk Support, then they always tell us that our modem appears to be properly connected.  Generally the Support Desk initiates a remote manual reboot (or restart) and the problem is fixed.  We have numerous Case numbers that document this issue.   We have at least 12 case numbers listing the same repeating problem.

On three separate occasions – 3 different dates (with 3 separate Xfinity field technicians) the support desk has sent a technician to our house to troubleshoot the problem.  None of the field techs found any problems with our equipment or wiring.

None of our neighbors are having a network problem, but none of our neighbors use a MB-8611 modem.  We switched our MB-8611 for an Xfinity XB-8T router.  No reboot issues were noted while the XB-8T was installed.  However, we already own a very expensive ASUS “Mesh” Router system which is programmed for our needs.  Our ASUS router actually has more features than the Xfinity XB-8T.  Having 2 routers installed caused problems.  (The 2 routers ‘fought’ each other.)   We called Xfinity Support desk and they attempted to set the XB-8T router to being just a “bridge” (or modem only).  They could not make it work.  The XB-8T router uses 40 watts of energy.  It is almost too hot to pick up when in use.  The MB-8611 uses 18 watts.  I really do not want a device that consumes extra power and generates extra heat.  I live in south Texas and spend most of my electricity costs on cooling my house.  It is rarely cold here.  The XB-8T does more than I need.  I just need a modem.

 

Documentation:

I am including specific documentation on our network failures.  We have a ‘smart’ American Standard Thermostat that communicates every minute back to a host server outside of our house (WAN).  When it fails to communicate, then it sends us a cell phone notification and an email message alerting us that our network is down.  I have compiled all that data (alert messages) into a provided spreadsheet, but I am happy to send anyone the specific messages.  Our cell phones use our home (LAN) network.  However, when the (WAN) network goes down, then our cell phones start using up our mobile data.  Our cell phone mobile data usage (thru a cell tower) start costing us extra money when Xfinity is down. 

We implemented a temporary work-around where we installed a digital timer that turns off the power to the MB-8611 modem at 2:30 AM and restarts the power at 2:31 AM.  Also again at 3:45 AM, with a restart at 3:46 AM.  This is a brute-force work-around.  We have computer backups and other devices that communicate in the middle of the night.  This causes additional issues for us.  It does not solve the real problem that is being created at the Xfinity Servers.

Request:

Would someone from the Technical Software Support Team run specific ‘restart’ tests using a MB-8611 modem.  I think there is a problem with the ‘restart’ code for this modem brand.  When I read the “Xfinity User forum” – I see other customers with a MB-8611 complaining about the same problem.

The Tech Support team can contact me at any time.  I am happy to work with them to find a solution. 

 

Thank You,

Supporting documentation for my Xfinity outages.