[Rock3C] please release bootloader img from SPI Flash for boot on by M.2 2230 disk

I need Rock3C can boot from the M.2 hard drive, but it requires burning the SPI Flash to achieve booting. However, the article did not provide the method for releasing the bootloader and burning the SPI Flash on Rock3C.

If possible, please provide:

  1. A bootloader img that can boot into the M.2 hard drive.
  2. The method for burning the SPI Flash on Rock3C.

Thank you.

some page:
SPI Flash bootloader files for Rock 3C --> no bootloader file
https://wiki.radxa.com/Rock3/install/spi --> no Rock3C bootloader file and burn solution
SPI Nor Flash for booting from NVME --> just Rock3A
ROCK 3 MODEL C: Boot from M.2 or eMMC? --> no solution and file