> ## Documentation Index
> Fetch the complete documentation index at: https://docs.researchanddesire.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Web Flasher

> Flash firmware to your OSSM or RADR device using the browser-based Web Flasher

Update or reinstall firmware for OSSM and RADR directly in your browser—no separate download or installer required.

<Info>
  Before you begin, use a data-capable USB cable, charge or power your device, and close any apps that might use serial ports (Arduino IDE, serial terminals, 3D printer hosts, etc.).
</Info>

## Flash your device

<Steps>
  <Step title="Open the Web Flasher">
    Open the Web Flasher in your browser:
    <a href="/ossm/tools/web-flasher">Open Web Flasher</a>

    <Note>
      The Web Flasher requires a browser with Web Serial API support. Use the latest versions of Chrome, Edge, or Safari.
    </Note>
  </Step>

  <Step title="Connect your device">
    Plug your OSSM or RADR into your computer with a USB cable. When prompted, select your device’s serial port (often shown as “CP210x USB to UART Bridge”).

    <Check>
      The Web Flasher shows your selected port and enables the Connect/Flash controls.
    </Check>
  </Step>

  <Step title="Choose firmware and flash">
    Select your device (OSSM or RADR) and the firmware version shown in the flasher, then click <strong>Flash</strong>.

    <Tip>
      If you’re unsure which version to use, choose the latest stable release presented in the flasher.
    </Tip>

    <Check>
      After flashing completes, your device restarts automatically with the new firmware.
    </Check>
  </Step>
</Steps>

## Verify the update

* Reconnect the device in the Web Flasher to confirm it is detected without errors.
* For OSSM, wait for the homing routine to complete after reboot.
* For RADR, continue with pairing and controls in the Quick Start guide: <a href="/research-and-desire-remote/quick-start">RADR Quick Start</a>.

## Troubleshooting

<AccordionGroup>
  <Accordion title="Device not detected">
    If your computer doesn’t recognize the device, you may need a USB-to-UART driver (especially on Windows). Also try:

    * Use a different USB port or a known data-capable cable
    * Disconnect and reconnect the device, then refresh the Web Flasher page
    * Close other apps that might hold the serial port (Arduino IDE, serial consoles)

    <Tabs>
      <Tab title="Windows">
        Download and install the CP210x drivers from Silicon Labs:

        * <a href="https://www.silabs.com/documents/public/software/CP210x_Windows_Drivers.zip">CP210x Windows Drivers (direct download)</a>
      </Tab>

      <Tab title="macOS / Linux">
        Most systems include drivers out of the box. If needed, get the latest VCP drivers here:

        * <a href="https://www.silabs.com/software-and-tools/usb-to-uart-bridge-vcp-drivers?tab=downloads">Silicon Labs USB to UART Bridge VCP Drivers</a>
      </Tab>
    </Tabs>
  </Accordion>

  <Accordion title="Browser not supported or no serial prompt">
    * Use the latest Chrome, Edge, or Safari
    * If you previously blocked serial permissions, click your browser’s site permissions (lock icon) and allow serial ports, then reload
    * Firefox does not currently support the Web Serial API—switch to a supported browser
  </Accordion>

  <Accordion title="Flashing fails or gets stuck">
    * Unplug the device, wait 10 seconds, and reconnect
    * Try a different USB port/cable and refresh the flasher page
    * Restart your browser or computer and try again
    * Ensure no other app is using the serial port
  </Accordion>
</AccordionGroup>

## Related guides

<CardGroup cols={2}>
  <Card title="Web Flasher Tool" icon="bolt" href="/ossm/tools/web-flasher">
    Flash firmware directly in your browser.
  </Card>

  <Card title="RADR Quick Start" icon="rocket" href="/research-and-desire-remote/quick-start">
    Power on, pair, and start using RADR after flashing.
  </Card>

  <Card title="Device Support" icon="devices" href="/radr/guides/reference/device-support">
    Check currently supported and tested devices.
  </Card>

  <Card title="Troubleshooting" icon="wrench" href="/all-devices/troubleshooting">
    General troubleshooting tips and how to contact support.
  </Card>
</CardGroup>