The README text "To write the default keys in flash you can use this Sketch" has the wrong example.

I found the example https://github.com/arduino/ArduinoCore-mbed/blob/main/libraries/STM32H747_System/examples/QSPIFormat/QSPIFormat.ino does not work with the new boot loader because the boot loader uses MBED_WEAK BlockDevice *BlockDevice::get_default_instance() in PlatformStorage.cpp which means the instantiation of the QSPIBlockDevice in the example does not work as it's non-unique.

I think perhaps the intended example to be linked to is the enableSecurity example. This also has the same QSPI issue.

There needs to be a general warning regarding the use of the mcuboot loader and QSPI access along with a note the examples do not apply in ArduinoCore-mbed.