Hi Alejandro,
I created the file for the QSPI config based on info from the SoM provider, they use a similar config to boot Yocto based system, (by similar I mean they don't use the nxp IDE to program their system).
When I saw the resulting file, this was the same as the one in the reference I quote.
the note about "However, there are some registers I did not see mentioned in the guide but were modified":

In the NXP ide the setting as you saw them are:


As I mentioned it ia custom board, using a SoM, I don't have the option to instrument it to get the requested signals.
About the " For the following registers, can you provide more information as why you changed them? since I cannot access the memory documentation. " => The changes I did were based on the info from the SoM provider.
And they are the same as in the quoted ref.:


The QSPI config. are confirmed to work in a linux system.
The 500 ms timeout doesn't seem to be a problem for the code size loaded in SRAM (2.6Mb).
Do we have a way to confirm that the code is completed loaded? a flag to confirm?
Do we have further contrains about the use of NOR Flash loading to SRAM when using Ethernet, SPI, FreeRTOS?
If only the QSPI config. is the key for being able to boot from NOR Flash please provide further support.
Regards,