Hi @AldoG ,
We were trying to boot from NOR memory through ECSPI2. We flashed eFUSED, which is perfect and confirmed on another post.
We tried porting ECSPI2 to via using the following command.
We added mtdparts=spi1.0:3072k(uboot),8k(env),128k(dtb),-(kernel)' at the kernel boot log and copied the image using dd.
dd if=imx-boot-imx8mm-lpddr4-evk-sd.bin-flash_evk of=/dev/mtdblock1 bs=1k seek=1 conv=fsync.
We getting an Unsupported boot device .
We connected LA check. please refer below image.

We also tried /dev/mtd1 instead of /dev/mtdblock1. but we were unable to see output on the MISO line.
And also we tried with fspi image. We didnt see any console message.
please refer below.

SPL is failing for us on both cases.
We also referring the following link for reference.
Can you please clarify on this one please?