Opal 5 (i.MX53) SD card boot fail

Bill Randle <bill.randle@...>

I have an Opal 5 SOM and DevKit which is based on the i.MX53 ARD reference design, and am trying to get it to boot via the SD card. I'm using Yocto 3.1 (Dunfell) and meta-freescale (current). My custom machine file is a copy of the imx53ard.conf with WiFi support deleted and some other tools added in. After running 'bitbake core-image-sato' I have:
I uncompressed the gz file and wrote it to the SD card with bmaptool.

The system does not boot and there are no messages on the debug console USB serial port (which means U-boot didn't load). The hardware is good as it will boot the Windows CE image in NAND flash. Yes, I did change the boot config switches to select boot from SD.

My questions are:
  1. The last embedded project I did several years ago needed a SPL loaded on the SD card. I noticed some imx u-boot configs use the imx-uboot-spl-bootpart.wks.in, but the imx53* ones use the default imx-uboot-bootpart.wks.in script. Will the internal i.MX53 firmware load U-boot directly without the need for the SPL?
  2. Does anyone who has used the i.MX53 have any suggestions on how to debug this, being as I see nothing on the console? If saw something/anything from u-boot, I would have a starting point and would know how to proceed.

This is obviously an old board, as nobody makes i.MX53 dev kits anymore (at least ones that support NAND flash). The board vendor had contracted with a third party (TrygTech) to provide Linux support. I did try to contact them via both email and phone, but have received no response to date.