BYOD modem firmware, capping speeds

I pay for 500 Mbps service with Xfinity but my speeds are capped at ~25 Mbps. My modem (Arris S33v2) is FCC-certified and listed on Xfinity’s approved BYOD list. The issue is not with my setup — I’m a certified network engineer, and I’ve done the due diligence of testing this extensively. Signal levels are perfect, cabling has been replaced, the modem has been reset/reprovisioned multiple times, and I’ve tested direct-to-modem. The problem is very clear: Xfinity refuses to push the required firmware updates to BYOD devices.

My modem is stuck on a 2022 firmware build. Without updates, it cannot properly provision and always falls back to a low-speed profile. Comcast admits my account is provisioned for 500 Mbps, but instead of resolving the firmware issue, support blames my “unsupported” equipment and tries to upsell me on renting their modem.

This isn’t just my case — it’s a systemic issue. Xfinity is effectively discouraging BYOD by withholding firmware, despite FCC rules (47 CFR §76.1206) requiring ISPs to allow compatible customer-owned equipment.

What you can do:
If you’ve run into this with your BYOD modem, file a complaint with the FCC: https://consumercomplaints.fcc.gov → Internet Service → “Billing, Service, or Speed.” Comcast must respond within 30 days. The more complaints filed, the more pressure we apply to get them to fix this and properly support customer-owned modems.