Thanks for this link.
Do you know whether secure boot supports on NAND flash too?
Our FAE donwload the same BSP (L4.9.11_1.0.0) without any patch and just enabled SECURE_BOOT flag as mentioned in AN4581.pdf, it can boot up from SD card or SPI flash no matter this boot image is signed or not.
PS. our EVK is a open device (We don't blow fuse to close it.)
But it's failed to boot up from flash (SECURE_BOOT is enabled and UBOOT_CONFIG = "nand") no matter this boot image is signed or not. (This EVK is reworked to boot from NAND flash. It can boot up if SECURE_BOOT is disabled.)
Do you have any advice for this symptom or is there any patch for this issue?