| Problem | Likely Cause | Solution | |---------|--------------|----------| | USB drive not recognized | Drive size > 8GB or not FAT32 | Use a 2GB or 4GB USB 2.0 drive. Reformat FAT32. | | Upgrade stalls at 50% | Corrupt firmware file | Redownload the file from NEC. Verify checksum. | | System won’t boot after upgrade | Incompatible firmware version (e.g., v1 hardware with v2 firmware) | You need a hardware-compatible version. Contact NEC support for recovery bootloader procedure. | | Phones register but no audio | DSP firmware not updated | Re-upgrade the DSP component separately using the same USB method. | | “Checksum error” in PCPro | File transfer corruption over serial | Lower your baud rate to 9600 and retry. Use a shorter serial cable. |
Locate the S1 switch on the main KSU. Press and hold the S1 switch while turning the AC Power switch ON.
If you have network access to the PBX, you can use the web interface.
: Always back up the system configuration data using PCPro before any update.
You will generally be given options on how to reset the system. It is highly recommended to select Immediately Reset so that the system applies the update and restarts as soon as the upload completes. Start the Process: Click Start or Upload . Critical Warning: Do not power off or disconnect the