SAMD51 (M4) board users: update your bootloaders to >=v3.9.0 Moderators: adafruit_support_bill, adafruit

[danhalbert]

If you have a SAMD51 board, including Metro M4, Feather M4, ItsyBitsy M4, Grand Central M4, Hallowing M4, PyBadge, PyGamer, PyPortal, or MONSTER M4SK, we highly recommend that you update the bootloader on your board to prevent internal flash occasionally being overwritten on power up.

For most boards this may just overwrite the loaded user program, but for a small number of boards that were shipped early in the product cycle, their bootloaders are not protected from overwriting, so this bug may brick the board, and require rewriting the bootloader manually, which can be difficult without external equipment or software.

There are directions for updating the bootloader in the primary product Learn Guide for each board, such as:
https://learn.adafruit.com/adafruit-fea ... bootloader
https://learn.adafruit.com/adafruit-pyg ... bootloader
https://learn.adafruit.com/adafruit-pyp ... bootloader
https://learn.adafruit.com/adafruit-pyb ... bootloader
etc.

[dconner]

I have a Feather M4 Express. I just installed the latest released version of CircuitPython on the board. I am working on a Chromebook and trying to check the UF2 bootloader for the correct version. I've tried to double-click the reset to view the bootloader (many times) and it does not work. All I get is CircuitPython disconnected and notified that a "removable device detected". The device is not recognized and it presents the option to format the device. I have not tried to format the device.

Any advice on how to proceed to check the bootloader?

[danhalbert]

@dconner It is possible the Chromebook is not recognizing the FEATHERBOOT drive. But how did you update CircuitPython, if double-click was not working? Did you copy the CircuitPython .uf2 file to CIRCUITPY, or to FEATHERBOOT? If you copied it to CIRCUITPY, then you have not really updated CircuitPython.

If you have access to any other machine, WIndows, Mac, or Linux, see if a double-click will present FEATHERBOOT.

FEATHERBOOT is a "fake" drive, so you cannot reformat it.

[dconner]

I got access to a Mac and checked the bootloader is v3.10 so it should be okay.

Initially when I plug in the M4 Express into the Chromebook the FEATHERBOOT drive is visible. After I drop the CircuitPython folder into FEATHERBOOT I never see FEATHERBOOT again on the Chromebook, even if I double-click the reset.

Thanks for the help.

[danhalbert]

Thanks for the testing. So are you saying after double-clicking, FEATHERBOOT does NOT appear on the Chromebook, but DOES appear on the Mac?

What brand and model of Chromebook is it?

Could you try this on the Chromebook? From the CircuitPython REPL:

Code: Select all | TOGGLE FULL SIZE

>>> import microcontroller
>>> microcontroller.on_next_reset(microcontroller.RunMode.BOOTLOADER)
>>> microcontroller.reset()

This should reset into the bootloader, without restarting CircuitPython. I would be interested in whether FEATHERBOOT then appears.

[dconner]

My Chromebook is an Acer Chromebook 14 CB3-431 MFG Date: 2017/12/07

When I run the 3 lines of code in the CircuitPython REPL then CIRCUITPY disappears from the directory. It appears to have the same effect as double-clicking the reset button.

While trying various resets with double-clicks I did see FEATHERBOOT appear in the directory for about one second and disappear. It may have been when double-clicking reset after a single click before CIRCUITPY showed up in the directory. I have not been able duplicate it and was not sure if those experiments were safe for the M4.

[danhalbert]

I have a new Chromebook on order for testing purposes and will try to replicate this problem. Thanks for the report.

[danhalbert]

@dconner: I received my Chromebook (Lenovo 82BA0000US), and was able to replicate the problem. What I see is that I can see the BOOT drive the first few times, but after several double-click cycles, the BOOT drive stop appearing. CIRCUITPY continues to appear.

I found that rebooting the Chromebook resets things. Also, it may help to deliberately unmount the CIRCUITPY drive before double-clicking to get the BOOT drive. See if that helps for you, and can be used as a workaround for now.

I will do some more testing later. It's fishy that the CIRCUITPY drive sometimes shows up with a sibling USB drive that is unreadable, underneath the board name. I have to click the ">" to point down to see both.

[dconner]

Rebooting my Chromebook and then double-clicking reset did make FEATHERBOOT appear. It seemed to take a long time (10-20 seconds) to appear the first time. It does seem to work more reliably when CIRCUITPY has been exited before double-clicking. I have tried it several times with success. Sometimes it doesn't seem work which may be due to variations in my double-clicking or some other reason.

It looks adequate to me as a workaround.