Falling sand on the STM32F411CE

Building

Run

make build

Probe for the board

Run

st-info --probe

Flashing

Run

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.