Version 4.00 introduced a major upgrade to the underlying SNE system which changed the mechanism used to install new firmware.
If your current version is older than version 4.00, then your upgrade must be performed in stages:
Current Version: 3.52 or older
Please contact support@calnexsol.com for further instructions.
Current Version: 3.6x
Upgrade to version 3.70 using the Windows GUI and then follow the steps below to upgrade from version 3.70 to version 4.00
Release Notes and Instructions: v4.00 Release Notes
3.70 and 4.00 Firmware: v4.00 Firmware
Current Version 3.70:
Upgrade to version 4.00 using the Web-based upgrade and then follow the steps below to upgrade from version 4.00 to the version you require
Release Notes and Instructions: v4.00 Release Notes
3.70 and 4.00 Firmware: v4.00 Firmware
Current Version 4.00 or newer:
All SNE releases from version 4.00 onwards are upgraded using the Web-based method. Please see the Release Notes and Instructions for the relevant release.