I am trying to bring up a custom iMX6UL board booting from eMMC, and encountering some issues.
I believe eMMC is hooked up properly. Via JTAG, I can load u-boot.bin (built from uboot-fslc-2017.11, the repo Yocto references) to 0x87800000. Then u-boot runs and gives me a console, from which eMMC works successfully ("mmc info", etc).
For production, we are using u-boot and SPL built from this code base:
I have loaded the compiled SPL to address 1kB and u-boot.img to address 69kB, as per the iMX6UL EVK. I used the command "dd if=SPL of=/dev/mmcblk1 bs=1k seek=1" to program the SPL for example. When I boot however, I don't see any console. I assume the SPL would print some message if it ran properly?
Based on scoping the eMMC signals, it looks like the iMX6UL ROM bootloader reads 4kB from the eMMC as described in the reference manual section 8.5.3. I verified the bytes at 1kB offset into the 4kB block read are the SPL file.
Other than scoping the eMMC signals, is there another way to verify the SPL works properly? Can I load it via JTAG to SRAM (perhaps address 0x908000?) and mimic a power-up boot?