Hello,
First, any attempts to execute a flash command while in HSRUN mode it will be trapped with the ACCERR bit. Please refer to section 28.4.9.1 of the reference manual.
The original startup configuration is FE
This means
- MCU security status is unsecure (The standard shipping condition of the flash memory module is unsecure)
- NXP factory access granted
- Mass erase is enabled
- Backdoor key access disabled
If you change it to EC, then
- MCU security status is secure
- NXP factory access granted
- Mass erase is disabled
- Backdoor key access disabled
During the reset sequence, the register is loaded with the contents of the flash security byte in the Flash Configuration Field located in program flash memory.