Xfinity Modem Flashing Green Light: Meaning & Fix
Quick Conclusion
A flashing green light on an Xfinity modem (e.g., XB7, XB8) typically indicates the device is booting up, performing a firmware update, or attempting to establish a connection with the ISP network. This is a normal operational state during startup or maintenance, not a severe hardware failure, but if persistent, it may signal a provisioning issue or network outage.
Engineer's Pro-Tip
Xfinity XB7 and XB8 gateways have a thermal management feature that can cause erratic flashing if overheated; keep the modem at least 6 inches from walls and in a well-ventilated area to prevent throttling that mimics connection issues.
Community FixReddit
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Read original threadWhy is this happening?
- The modem is in the boot-up sequence after a power cycle or reset, initializing hardware and loading firmware.
- A firmware update is being downloaded and installed from Comcast's backend, often triggered automatically.
- The modem is attempting to synchronize with the DOCSIS network, scanning for downstream and upstream channels.
- A provisioning error or signal loss from the ISP, causing the modem to repeatedly try to connect.
Step-by-Step Fix Flow
Wait for Normal Boot Completion
Allow 5-10 minutes for the modem to complete its boot process. During this time, avoid unplugging it, as flashing green is standard for startup or updates.