I didn't think that it was  - I don't get the defmt message. Only the hard fault handler.
```
#[cortex_m_rt::exception]
unsafe fn HardFault(_frame: &cortex_m_rt::ExceptionFrame) -> ! {
    defmt::error!(<different msg>);
    loop {
        debug::exit(debug::EXIT_FAILURE);
    }
}
```