Error Code Power LED red during boot-up/firmware upgrade process

Router is undergoing a firmware upgrade; do not interrupt this process.

? What Causes This

Automatic or manual firmware update initiated, potentially initiated from the web GUI.

✓ How to Fix It

Do not intervene during any firmware updates; wait until all LED indicator statuses return to normal indicating reboot completion. If issues persist after upgrade, refer to troubleshooting steps provided by manufacturer.

Source: page 46 of the official manual

From the manual

Manual page 46 — Sagemcom error Power LED red during boot-up/firmware upgrade process

This error code appears in:

Sagemcom CS 50001