M2 LED is blue and can't bootloader

[Sama]

Dear all

I have been using Crazyflie for a month without any major issues, but today I have noticed that only M2 led is on (blue) without blinking and the rest of LEDs are off.

I tried to fix it by putting Crazyflie into bootloader mode (This is not my first time I did it once and it was successful), but when I use the lsusb it does not show that there is a device in DFU mode. So, it is not recognized by the computer as a USB device.

I tested it on VM and Ubuntu machine both failed.

I tried cold bootloader and it gave me could not conncted to bootloader

Please help me with possible solution

[kimberly]

Hi, have you been using the dfu mode to flash the firmware usually or always the crazyradio PA? We usually advise to only use the cfload way since that is the savest.

This forum thread did also mention the same issue as you are having: viewtopic.php?f=5&t=2640&p=18174&hilit= ... lue#p18174. Maybe you can try the fixes mentioned in there as well.

[Sama]

I usually use DFU mode to flash the firmware
But now as it showed in the attached image the VM cannot recognise the existence of crazyflie, even if I use it on the native setting and try lsusb ?

[tobias]

Can you get into the bootloader by doing a cold boot? That is by holding down the button while connecting the battery?

[Sama]

Crazyflie Radio can find the quadcopter and connect to it. Even if I used my mobile I can connect to the quadcopter. However, Nothing more happened only M2 LED is on and blue.

Even the cold boot has failed as it shown in the attached image.

[arnaud]

If only M2 is lit, it means that there is a problem with the STM32 firmware. Assuming you have not been playing with a debug probe or with DFU, the STM32 still has its bootloader intact and ready to go.

If the radio chip is still intact you can launch the bootloader normally by pressing the button more thatn ~2seconds and both M2 and M3 should blink, this indicates that both CPU are in bootloader mode and cold boot will work.

If the radio chip firmware also has a problem, you can:
- disconnect the battery
- press the button
- connect the battery
- When M2 starts blinking, release the button

Then both blue LED will blink and you can connect the bootloader.

As a background info: on the Crazyflie, the radio chip is always powered and handles the button and power management. M2 is connected to the radio chip while the 3 other LEDs are connected to the STM32 main MCU. So only seeing M2 means that there is something wrong with the STM firmware. Bootloaders are not able to write over themselves or modify the radio chip boot process, this means that as long as you only use radio bootloading there is no way to brick the Crazyflie and the procedure I explained above will always be able to start the bootloaders.

Can you get the Crazyflie in a state where M2 and M3 are blinking (ie. bootloader mode on both CPUs)?

[Sama]

Thank you Mr. Arnaud for the background information.

Unfortunately, I could not make M3 blinking with all of these methods.

I feel there is a heat between m2 and the usb when I plugged Crazyflie to the USB ? Does it indicate something such as short circuit problem ?
I unplugged it once I felt the heat.

Thank you all for your replies, appreciated.

[arnaud]

The battery charger is not far from the USB port so it is possible the heat you felt comes from there if you have an uncharged battery connected.

You mention you have been using DFU to flash your Crazyflie earlier in this thread, are you sure you did not remove the bootloader from the STM32 by doing so? Generally speaking DFU mode should not be used as it has more risk of causing problems, we prefer using the radio bootloader that has no risk of bricking anything.

For entering DFU mode I assume you know the procedure: press long on the power button until the M2 led blinks fast. I have had some time a bug that requires to click one more time on the power switch to make the device appear on usb, maybe this is what is happening to you.