Updating the bootloader
The UF2 bootloader is a new bootloader, and while we've done a ton of testing, it may contain bugs. Usually these
bugs effect reliability rather than fully preventing the bootloader from working. If the bootloader is flaky then you can
try updating the bootloader itself to potentially improve reliability.
In general, you shouldn't have to update the bootloader! If you do think you're having bootloader related issues,
please post in the forums or discord.
Updating the bootloader is as easy as flashing CircuitPython, Arduino or MakeCode. Simply enter the bootloader as
above and then drag the update bootloader uf2 file below. This uf2 contains a program which will unlock the
bootloader section, update the bootloader, and re-lock it. It will overwrite your existing code such as CircuitPython or
Arduino so make sure everything is backed up!
After the file is copied over, the bootloader will be updated and appear again. The INFO_UF2.TXT file should show the
newer version number inside.
For example:
UF2 Bootloader v2.0.0-adafruit.5 SFHWRO
Model: Metro M0
Board-ID: SAMD21G18A-Metro-v0
Lastly, reload your code from Arduino or MakeCode or flash the
Below are the latest updaters for various boards. The latest versions can always be found
Look for the
update-bootloader...
© Adafruit Industries
files, not the
bootloader...
https://adafru.it/Bmg
https://adafru.it/Bmg
https://adafru.it/Bmi
https://adafru.it/Bmi
https://adafru.it/Bmj
https://adafru.it/Bmj
https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51
latest CircuitPython core
files.
(https://adafru.it/tBa).
here
(https://adafru.it/Bmg).
Page 180 of 183
Need help?
Do you have a question about the Feather M4 Express and is the answer not in the manual?