I use official board and SDK libraries. I write my project in MDK.
I set the MCU in secure status and enabled backdoor key access.
When I use FLASH_SecurityBypass() function from library, function returned me FLASH Access Error status.
I entered the same backdoor key which is in FCCOB registers. For key entering I use terminal window.
The problem comes from FLASH_SecurityBypass() function where call flash_command_sequence() function.
flash_command_sequence() function returned FLASH Access Error status.