SPL/UBOOT sometimes hangs while tryning to load core fw

Hello,

I'm working on a custom board with a SoCFPGA Altera Arria 10. I'm working in Altera Environment 20.1 and U-Boot 2020.04. I have a firmware file that includes periph and core . This file is stored on the QSPI flash. The SPL loads the periph part, initializes the DDR, loads the core, part and then loads the U-Boot. After that, the U-Boot loads a VxWorks image.

I have a strange error: every 10 times (give or take) that I turn on the board, there is one time that the SPL isn't able to load the core firmware, meaning the SPL just gets stuck or hangs while trying to load the core instead of displaying "Full Configuration Succeeded" and "FPGA: Enter User Mode". When it hangs, the terminal stops responding. This happens only sometimes and randomly.

Do you have any idea what can cause this and how to fix it?

Why would the load of the core be successful sometimes and unsuccessful other times?

I tried to load the core at the U-Boot part but I get the same result; it hangs while trying to load the core only once every few turn-ons of the board.

My main problem is that I can't tell if the problem comes from the core fw part that I try to load or because of the SPL+UBOOT that weren't configured right.

In an earlier version we used UBOOT 2014.01 and Altera 17.1, there we didn't have SPL+UBOOT only UBOOT: maybe it's has to do with that?

I build my SPL+UBOOT using this doc on section "Arria 10 SoC - Boot from QSPI"

https://www.rocketboards.org/foswiki/Documentation/BuildingBootloaderCycloneVAndArria10#Arria_10_SoC_45_Run_U_45Boot_from_Debugger

Maybe I need to switch from some reason to Altera 23.1 ? I'm not sure that it will solve the problem.

Thanks in advance, any help would be appreciated ,
Yoel