2 years, 3 months ago.

FAIL.txt application file format is unknown

I'm trying to run the Nucleo_blink_led example on my Nucleo-F446RE but as soon as I drag the .bin into the drive it reboots and returns a FAIL.txt that says: The application file format is unknown and cannot be parsed and/or processed.

It then seems to reboot or something? I'm not sure exactly what happens it just disappears from list of devices and comes back and the led blinks for a couple of seconds. Doesn't stop until I pull the plug.

Thanks for reading this.

7 Answers

2 years, 1 month ago.

Has anyone found how to correct that?

2 years, 1 month ago.

I am having the same issue

2 years, 3 months ago.

Hi there,

I would make sure that your Nucleo-F446RE has the most up to date firmware. Instructions to update your board's firmware can be viewed here: https://os.mbed.com/teams/ST/wiki/Nucleo-Firmware

Please let me know if you have any questions!

- Jenny, team Mbed

Yes, firmware is updated.

posted by L H 04 Apr 2018

Same issue with a Nucleo-F401RE with up-to-date firmware (V2.J30.M20).

posted by Christoph Berger 04 Apr 2018

I'm having the same problem with a Nucleo-64 STM32F302. Firmware is up to date. Even a simple program with a few lines produces this error. I can make the behavior stop only if the power to the board is cycled.

posted by Mark Villela 28 Apr 2018
2 years, 3 months ago.


I'm having the same problem with a Nucleo-F401RE, firmware is up to date (V2.J30.M20). Even a simple program (just switching on a LED) will produce this error, so I guess it's either an issue with ST's firmware or the binary file.

2 years, 3 months ago.


I am also having the same issue with a Nucleo f401re i updated the firmware to v2.j30.M20, only difference being, is that once i ugraded the firmware, the board kept restarting the USB port and MCU continuously, i still have no idea what the fix is , however i think its a bug in the new firmware and its causing a boot- loop of sorts.

2 years, 3 months ago.

Please read this post:


This post is not related to the problem being reported.

posted by Mark Villela 28 Apr 2018
1 year, 12 months ago.

I'm having the same problem - firmware is upgraded to 2.31.21 - when i transfer the .bin, device resets and binary is not loaded - old program continues to run - i get the fail.txt message highlighted above - 'the application file format is unknown...'