# Falling sand on the STM32F411CE

## Building
Run
```sh
make build
```

## Probe for the board
Run
```sh
st-info --probe
```

## Flashing
Run
```sh
make flash
```

## Debugging

### `st-info --probe` shows 0KB flash
```
> sudo st-info --probe
Found 1 stlink programmers
  version:    V2J43S28
  serial:     0671FF343056363043090732
  flash:      0 (pagesize: 16384)      <--- 0KB flash
  sram:       131072
  chipid:     0x431
  dev-type:   STM32F411xC_xE
```
This can happen when the flash is locked. One way to unlock it is to erase the entire chip via the
Windows application `ST-Link Util`.