Allow to uset ST-Link Util as SPI flash Reader/Writer. Tested with STM32F411 miniF4 DevBoard.
Copy MX25L25645G.stldr to "C:\Program Files (x86)\STMicroelectronics\STM32 ST-LINK Utility\ST-LINK Utility\ExternalLoader"
For more info look at ST-Link UTIL Manual chapter 5