Update the Bootloader on your QT Py SAMD21

QT Py SAMD21 top view QT Py SAMD21 bottom view

If you have an Adafruit QT Py SAMD21 (product 4600), we recommend that you update the UF2 bootloader on the board.

Some recent samples of this board were shipped without bootloader write protection. A power glitch may cause the bootloader to be erased. This problem is rare, but re-flashing the bootloader is not a simple task. Updating the bootloader will bring it to the latest version, and as a side effect, will properly protect the bootloader in the future.

Here are complete instructions for updating the bootloader. You can check the version of the bootloader on your board by looking at the INFO_UF2.TXT file when the QTPY_BOOT drive is visible. If the bootloader version is earlier than v3.15.0, we advise you to update it.

Version v3.15.0 speeds up the updating process compared to earlier versions, and also will prevent the board from booting if the supplied voltage is lower than 2.9V or so. This ameliorates the power-glitch susceptibilty mention above.

This recommendation applies only to QT Py SAMD21 boards specifically (the “original” QT Py), not QT Py RP2040 or ESP32-nn boards. The other QT Py boards are unaffected by this issue.


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