small update...
last tries I've made:
with an SD card loaded with armbian 26.2 (from Armbian archives) and DIP on SD, the boot is ok, boot is U-Boot 2025.10_armbian-2025.10-Se50b-P915a-H3623-V44f7-B2eb2-R448a. However, no option to load bootloader in SPI present in nand-sata-install, most probably because no SPI block listed in lsblk output. nan-sata-install complains that the command line is incomplete and request to try option 'help', but I could not figure how to get to the help, any common option passing I've tried did not worked.
I tried to get to the initial install procedure from Kobol, modifying the spi_workaround from off to on in armbianEnv.txt on the SD, but this prevent the kernel to boot from SD.
Any help would be appreciated...