reproduced. it's rtt buffer being full and blocking the second core. recovery requires that the spinlock is cleared before main.

```
#[cortex_m_rt::pre_init]
unsafe fn before_main() {
    // Soft-reset doesn't clear spinlocks. Clear the one used by critical-section
    // before we hit main to avoid deadlocks when using a debugger
    embassy_rp::pac::SIO.spinlock(31).write_value(1);
}
```

I think this is also a probe-rs issue, it should not be leaving RTT in blocking mode when disconnecting