Click or Open and select the hex/bin firmware file corresponding to the U1 update. Click Update or Start .
Completely disconnect the battery for 5 minutes to force a hard reset, then reconnect it.
Connect your Windows laptop to the inverter's communication port using your serial cable. Open Windows Device Manager to verify which COM port number has been assigned to your USB adapter. 2. Launch the Reflash Tool
Click "Browse" or "Open" to locate and select the corresponding .hex or .bin file if it isn't automatically pre-loaded. Click or Start . axpert vm iii firmware
If the software tool states "Connection Failed" immediately, your COM port selection is incorrect, or your USB-to-Serial adapter driver is missing. Install the official Prolific or FTDI drivers for your cable. Update Stalled at Midpoint
Match your specific CPU version (U1 or U2).
If your firmware update stalls or fails, do not panic. Most issues can be resolved by checking your connection settings. Record Failed Error Click or Open and select the hex/bin firmware
While updating the Axpert VM III firmware is generally a smooth process, issues can arise. Here are some common problems and troubleshooting tips:
Right-click on ReflashTool.exe (or the specific executable provided) and select . Phase 3: Executing the Flash
Right-click the Reflash Tool executable and select . Connect your Windows laptop to the inverter's communication
Resolves known communication issues with external monitoring software like SolarAssistant, WatchPower, or Home Assistant setups. Understanding Axpert VM III Firmware Architecture
The inverter LCD screen will blank out or display "UPL" during the update. This behavior is normal.