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  1. This Guide explains the Firmware loading process for OpenEVSE.
    • This Guide explains the Firmware loading process for OpenEVSE.

    • This guide is specifically intended for the Windows Operating system. Advanced users may use a similar process for MacOS and LINUX.

  2. Download Windows Driver for the OpenEVSE Programmer.  Using this guide.
    • Download and install the WinAVR software. WinAVR

    • Select BOTH the Install Files and Add Path Options. Developers Notepad is Optional.

    • Connect Programmer to OpenEVSE then connect to USB port on PC.

    • The yellow wire on the 6 pin connector aligns with pin 1 of the ISP connector.

    • Download a pre-compiled HEX file from the OpenEVSE Sources for your OpenEVSE product and your desired configuration.

    • Download the latest firmware and save files into a local folder. You will need 3 files: flash.bat, open_evse.hex and eeprom_24.bin

    • Run the flash.bat file. Programming and verification should take about 60 seconds.

    • If the command window pops up and goes away immediately there is a problem with the Device driver and/or the WinAVR installation.

    • Warning can not set SCK period is normal and can be ignored.

Finish Line

8 other people completed this guide.

Christopher Howell

Member since: 07/05/2014

5,287 Reputation

16 Guides authored


You can get a signed version of the USBasp driver from

Should make things a lot easier.

Daniel - Reply

Correction: the batch file for all newer firmware versions is "flash.bat"

donahuepaul - Reply

The firmware link in the store just points us to the GitHub repo. Where can I find the pre-compiled versions of the firmware?

teslatradeup - Reply

Pre-Compiled versions are located at:

OpenEVSE Github

Default Firmware Loads

Christopher Howell -

The USBasp that I got had a ribbon cable. Orientation of the cable is tricky - The key on the cable jams into a part on the OpenEVSE board. I had to shave off the key to get things to work. Once I did that, things work great. Even from iOS, writing with the Arduino software.

Ed Hubbell - Reply

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