[Connectivity] Strange issue finally resolved A few months ago, I posted here about some issues I was having with my modem freezing/rebooting several times a week. I had also been calling in every month or two for the last six or so months to check on upgrade availability.
Last month, I made another routine call to pester them about upgrades. Usually whenever I call, the tech would attempt to apply the faster-tier codes to my account, with it failing inexplicably. We'd usually chalk it up to it not being here yet, and leave it at that. This time, they dug into it a bit more. I ended up being on the phone for nearly an hour, with the CSR talking to internal support and supervisors, as she felt that I definitely should be able to upgrade to faster tiers. She said that tech support had told her that my modem wasn't DOCSIS 3, even though she and I knew that the SB6120 was; both from common knowledge, and that I had just hit nearly 110 Mbps in a speed test. She scheduled a tech to come out the following Monday (June 11th) to physically inspect my setup.
The tech that came out was the one that did the initial business install and remembered my equipment setup. He was baffled as to why I wouldn't be able to upgrade, although he mentioned I was the first 50 Mbps inquiry/upgrade he had seen here (probably would help if the Comcast site listed more than Economy/Performance/Blast). He said that while he was dispatched for a business call, he was actually residential support (apparently there's no dedicated business techs up here) and thus wasn't able to do much with my account. He said he'd notify his boss, who would call me later that day.
By that Friday, the 15th, I had still not received a call, so I decided to call again that morning. I was going out of town for a day or two, so I figured I'd try to get the ball rolling while I was gone. That CSR also said something strange was going on with my account. She noticed that my modem was listed strangely, it had the model number listed, but wasn't apparently flagged as any particular DOCSIS version. She also noticed that I was using my own modem on business since I signed up for it in early 2011, and told me they weren't allowed to do that until early this year. Apparently when they did it for my account, they had to custom-add the modem to my account, which was causing the weirdness.
She decided to remove the modem from my account and re-add it. That ended up being the magic trick. Once she added it as a standard business SB6120, she had me power cycle the modem. Bam, 50/10 with no hiccups!
Since then, I've been monitoring my modem. It's been performing absolutely flawlessly since then. There's been occasional weird entries in the modem log (stuff I had never seen before and didn't get many useful results on Google), but my T3 timeouts have nearly vanished (one today, first one in a couple of weeks), and zero reboots. I had an uptime of 30 days before resetting the modem earlier tonight to see if I would get new firmware.
I figured I would post this since I've seen a few other people here using their own modems on business since before Comcast officially allowed it, and may possibly end up with the same issue.
tl;dr - Modem delete/re-add fixed my reboot issue.