UBoot doesn't start from SPI Nor Flash

Hi,
I’ve created simpliest image for SD so that I could reach u-boot.
rock-3a-idbloader-gef9f6b1caad.img under 64 offset and rock-3a-u-boot-gef9f6b1caad.itb under 16384. Whole img is 11MB.
While written to SD and attached to device - after power reset it reaches `FIT: No FIT Image" and enters U-Boot command line mode.

WHY the same sequence written to Flash (following this instruction - fails? What I need to do to reach U-Boot from Flash
Maskrom state reached with - rkdeveloptool db rk356x_spl_loader_ddr1056_v1.12.109_no_check_todly.bin

PS: Flash is present and that’re its details.

=> rkdeveloptool rid
Flash ID: 4E 4F 52 20 20
=> rkdeveloptool rfi
Flash Info:
        Manufacturer: SAMSUNG, value=00
        Flash Size: 16 MB
        Flash Size: 32768 Sectors
        Block Size: 128 KB
        Page Size: 2 KB
        ECC Bits: 0
        Access Time: 40
        Flash CS: Flash<0>