flash my own bootloader and my own application using the usbc

[AhmedMahmoud]

SA all,

in My Project Iam using a STM32f401RCT6 (blackpill) ,and i wanna flash my own bootloader cause iam impelementing a OTA (FOTA) project , and i am able to flash the code using usbc but it uses the default bootloader either the stmcubeprogrammer nor the arduino ide , and i dont have a hardware programmer ,

is it possible to flash my own bootloader and my own application using the usbc? 

[Tesla DeLorean]

Perhaps look at the DFU Device project?

Probably other examples in the same vein

https://github.com/STMicroelectronics/STM32CubeF4/tree/master/Projects/STM324xG_EVAL/Applications/USB_Device/DFU_Standalone