Warning

The S32K1xx devices can be locked out by flashing bytes at specific memory location.

You must define the following section in your linked script.

SECTIONS
{
  .flash_config 0x400 :
  {
    KEEP(*(.flash_config));
  } > FLASH
} INSERT AFTER .vector_table;

Then, you must fill it with the following content.

#[repr(C, packed)]
struct FlashConfig {
    backdoor_key: [u8; 8],
    fprot: [u8; 4],
    fsec: u8,
    fopt: u8,
    feprot: u8,
    fdprot: u8,
}

#[used]
#[unsafe(link_section = ".flash_config")]
#[unsafe(no_mangle)]
static FLASH_CONFIG: FlashConfig = FlashConfig {
    backdoor_key: [0xFF; 8],
    fprot: [0xFF; 4],
    fsec: 0xFE,
    fopt: 0xFF,
    feprot: 0xFF,
    fdprot: 0xFF,
};