NUCLEO-F767ZI unable to do a FullChipErase

[iw2lsi]

Hi,

i was playing with OptionBytes on my custom USB-Bootloader and... I end up in a bricked NUCLEO board... the CPU itself is still running (I can even update an application) but I cannot connect via ST-LINK and/or DfuSe anymore...

The error message is:

09:12:27 : Can not connect to target!

         If you're trying to connect to an STM32W1xx device, please select Normal or HotPlug mode from Target->Settings menu.

         If you're trying to connect to a low frequency application , please select a lower SWD Frequency mode from Target->Settings menu.

09:12:28 : No target connected

On the device folder:

DETAILS.TXT

------------------

Version: 0221

Build:  Sep 18 2018 11:09:21

FAIL.TXT

------------

The interface firmware FAILED to reset/halt the target MCU

ST-Link utils is v4.3.0.0

ST-LinkUSB-Driver is v5.1.0.0

ST-Link CLI is v3.3.0.0

The option "connect under reset" & pressing the B2 (reset) button before doing a chip erare seems not to work... somewhere there is a note regarding SB111 (pad between NRST-RST) but in my case a 0 ohm resistor is already there.

Any ideas on how to unbrick my NUCLEO board ?

thanks,

Giampaolo

[Uwe Bonnes]

Try connect under reset or USB DFU.

[iw2lsi]

Hi Uwe...

I've already done this... and it did not work... I think I'm somehow in Level 2 protection:

Level 2 is an irreversible operation. When Level 2 is activated, the level of protection cannot be decreased to Level 0 or Level 1.

Giampaolo

[AvaTar]

> Try connect under reset or USB DFU

Booting into system mode, and try a mass-erase there ?

Not sure if this is meant to be the same.

> I think I'm somehow in Level 2 protection:

>Level 2 is an irreversible operation. When Level 2 is activated, the level of protection cannot be decreased to Level 0 or Level 1.

Then you have bricked it probably ...

[iw2lsi]

uh...

I was convinced that full chip erase was always possible... but it seems that I was wrong... my bad.

Giampaolo

[Uwe Bonnes]

There are hacks out there that that will turn Level 2 into level 1. Look at the CC (Computer Chaos ) Club conferences talks. In short, they turn on the chip and turn off at the right moment. But buying a new Nucleo is much less effort.

[iw2lsi]

Hello Uwe...

.. I was also thinking at replacing the MCU... but since it costs $13 while the whole board is $20... it's a nonsense...

I've done a search for CCC and STM32 Level 2 but got nothing... do you have a link to the paper you are talking about ? I'm just curious....

tnx

Giampaolo

[Uwe Bonnes]

https://media.ccc.de/v/35c3-9563-wallet_fail

[iw2lsi]

amazing!

tnx Uwe...