[U-Boot] U-boot multi-file format

Hi all,

I'm trying to use the multi-file format mentioned in pages 12-13 of "U-Boot – Multi image booting scenarios" PDF slides.

I'd like to use FIT format, but I already have units in the field without CONFIG_FIT.

So I'd like to use the legacy U-Boot multi-file format, but I don't understand the format that should be used for the ramdisk. I already have a multi-file image that boots the kernel with the dtb, but it crashes when the ramdisk is needed (looking for an address outside of physical memory limits).

Which format should be used for the ramdisk? ext3.gz initrd? cpio.gz initramfs?

Thanks for any help!

Bests, Diego