Symptoms
When attempting to upgrade camera firmware, the upload repeatedly fails through:
The camera web interface (browser-based upload)
The Oncam C-Series Camera Configuration Tool (CCT)
Additional observations may include:
The progress bar stalls or abruptly fails
Uploads timeout across multiple browsers (Chrome, Edge, etc.)
Disabling Wi-Fi or trying alternate network adapters has no effect
The upgrade succeeds immediately when the camera is isolated on a PoE injector or unmanaged switch
Cause
Firmware upgrade failures typically occur when network-level interruptions or filtering affect the HTTP upload session between the PC and the camera.
Common contributing factors include:
Managed switches performing port monitoring, LLDP negotiation, or power resets
Traffic inspection or flow control interfering with large file uploads
Multicast, VLAN, or QoS filtering dropping portions of the upload
Polling traffic from recording or management systems
Power fluctuations or link renegotiation during the flash-write phase
During firmware upgrades, the camera temporarily reduces response to network traffic as it unpacks and writes to flash. If the network equipment interprets this as a communication failure, it may momentarily drop or reset the port, interrupting the upgrade.
Resolution
To ensure reliable firmware upgrades:
Isolate the camera on a direct connection using a PoE injector or simple unmanaged switch.
Connect the camera and your PC directly, bypassing managed switches or recorders.
Disable antivirus or firewall software temporarily during the upload.
Avoid network paths that traverse recorders or management systems actively polling cameras.
Verify link stability by forcing 100 Mb Full-Duplex and disabling EEE or LLDP on the PC port if adjustable.
Retry the upgrade using the same firmware file.
Once upgraded successfully, the camera can be returned to its production network.
Best Practice
Always perform firmware upgrades in a controlled, isolated environment.
Avoid running upgrades over managed, monitored, or production network paths.
Document network conditions (switch model, firmware version, port configuration) if issues persist.