NXP Semiconductors K32 L2A Series, Reference Manual, Page: 254 / 1379

When the ROM is executed out of reset, vector fetches from the CPU are redirected to
the ROM's vector table in ROM memory at offset 0x1C00_0000. This ensures that any
exceptions will be handled by the ROM.
After the Kinetis Bootloader has started, the following procedure starts bootloader
operations:
1. The RCM_MR [BOOTROM] bits are set, so that the device will reboot back into the
ROM if/when the device is reset.
2. Initializes the bootloader's .data and .bss sections.
3. Reads bootloader configuration data from flash at address 0x3C0. The configuration
data is only used if the tag field is set to the expected 'kcfg' value. If the tag is
incorrect, then the configuration values are set to default, as if the data was all 0xFF
bytes.
4. Clocks are configured. See the Clock Configuration section.
5. If BOOTSRC_SEL is set to 0b10, then the QSPI0 interface is configured by reading
the configuration block from the base address of the external QuadSPI, or from the
address pointed by the qspiConfigBlockPointer in the BCA.
6. Enabled peripherals are initialized.
7. The bootloader waits for communication to begin on a peripheral.
• If detection times out, then the bootloader jumps to the user application in flash.
See Bootloader Exit state section.
• If communication is detected, then all inactive peripherals are shut down, and the
command phase is entered.
NOTE
The flash sector containing the vector table should not be
located in the execute-only region, because the Kinetis
bootloader cannot read the PC and SP addresses in an
execute-only region.
Functional Description
K32 L2A Reference Manual, Rev. 2, 01/2020
254 NXP Semiconductors