Flashing

Upload compiled firmware to your VESC using a SWD debugger or VESC Tool over USB.

There are two methods to flash firmware onto a VESC: using a SWD hardware debugger, or uploading via VESC Tool over USB.

Method 1: SWD debugger

Requires STLink or compatible JTAG/SWD probe. Needed for first-time flashing and recovering a bricked device.

Method 2: VESC Tool USB

Upload a .bin file through the VESC Tool application. No extra hardware required once a bootloader is present.

Method 1: SWD debugger

This method uses OpenOCD and a SWD/JTAG probe (such as an STLink v2) to write firmware directly to the device.

1. Flash the bootloader

   Before flashing application firmware for the first time, you must flash the bootloader. Clone and build the bldc-bootloader project and follow its instructions.

2. Build your target firmware

   Build the firmware for your board:

   make 100_250
   
3. Flash the firmware

   Use the _flash make target for your board. For the VESC 100/250:

   make 100_250_flash
   

   This invokes OpenOCD to write the compiled .elf to the device over SWD.

On Linux, you can use the STLink v2 programmer without root access by installing the udev rules. See Prerequisites for the commands.

Method 2: VESC Tool USB upload

This method uploads a compiled .bin file through the VESC Tool application over USB. A working bootloader must already be present on the device.

Do not disconnect power or USB from the VESC during the upload process. Doing so risks bricking the device.

1. Build the firmware

   Build the .bin file for your board:

   make 100_250
   

   The output file is located at build/100_250/100_250.bin.

2. Connect to the VESC in VESC Tool

   Open VESC Tool and connect to your VESC over USB.

3. Navigate to the Firmware tab

   Select the Firmware tab from the left side menu.

4. Select your firmware file

   Click the Custom file tab, then click the folder icon to browse for and select your .bin file (e.g. build/100_250/100_250.bin).

5. Start the upload

   Press the upload firmware button (downward arrow) in the bottom right to begin the upload.

   It is normal for VESC Tool to show a disconnect during the upload process.

6. Wait for completion

   Wait for the loading bar to complete, then wait an additional 10 seconds before disconnecting anything.

   Disconnecting power or USB before the 10-second wait completes after “FW Upload DONE” risks bricking your VESC.

7. Reconnect

   The VESC will disconnect itself once the new firmware is running. You can then reconnect in VESC Tool.

If your VESC is bricked

A bricked VESC cannot accept USB firmware uploads because the bootloader is no longer functional. To recover:

1. Use a SWD debugger (Method 1 above) to re-flash valid firmware directly.
2. You must flash the bootloader first, then the application firmware.

A SWD debugger is the only way to recover a bricked VESC. Keep one available if you are frequently updating firmware.