Use Chrome or Edge (Web Serial required). Safari currently does not support Web Serial.
Note: Your SAMD21 must already include a UF2-capable bootloader (KraftorBOOT) for this workflow.
1. Connect Device
Select your SAMD21 device via serial port
No device selected
2. Start Bootloader
Reboot device into bootloader mode
Serial port will disappear when successful.
Status: Waiting for device
connection...
3. Confirm/Pick Drive
After reboot, device appears as KraftorBOOT drive
No drive selected
Status: Waiting for reboot...
4. Upload Firmware
Select and upload UF2 firmware file
No file selected
Not ready
Status: Waiting for drive
selection...