Boot hangs, probably at SPL load when booting from SD card on Compulab IoT Gateway

[devgaia]

We can't seem to get the device to boot from SD card. Have built both full FFU and just firmware and have had the same result which is immediate hang on boot, no output in the terminal.

This is what we've done/tried:

• Applied E2 jumper to enable boot from SD Card. Able to boot Yocto from Compulab placed on SD card.
• Built FFU using instructions in Building the BSP and the applied to SD card using IoT Dashboard. Immediate hang!
• Created new SD card using diskpart and dd following these instrutions with just firmware. Immediate hang!
• From u-boot in MMC checked that fuses for SRK values are still 0. As far as I understand i.MX7D has HAB version 4.2.X and HAB 4.1.2 and higher only checks SRK values if SRK fuses are not 0.
• Build firmware from source using WSL following these instructions and then moving to SD card. Immediate hang!
• Build firmware from source using Ubuntu VM and then moving to SD card. Immediate hang!

How do I check that the device is in "Open Mode", and is that relevant?
The device is in "secure mode" what does this mean, and is it relevant for my problem?

When booting u-boot from MMC this is what I see from SPL:

`U-Boot SPL 2017.07-cl-som-imx7-1.5 (Jun 18 2018 - 13:02:48)
Booting from SPI flash
Trying to boot from SPI

U-Boot 2017.07-cl-som-imx7-1.5 (Jun 18 2018 - 13:02:48 +0300)

CPU: Freescale i.MX7D rev1.3 at 792 MHz
Reset cause: POR
I2C: ready
DRAM: 1 GiB
PMIC: PFUZE3000 DEV_ID=0x30 REV_ID=0x11
NAND: 0 MiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
SF: Detected w25q16cl with page size 256 Bytes, erase size 4 KiB, total 2 MiB
Video: 1024x768x24
In: serial
Out: vga
Err: vga
Board: CL-SOM-iMX7 in secure mode
Net: FEC0, FEC1
starting USB...
USB0: USB EHCI 1.00
scanning bus 0 for devices... 1 USB Device(s) found
USB1: USB EHCI 1.00
scanning bus 1 for devices... 1 USB Device(s) found
scanning usb for storage devices... 0 Storage Device(s) found
scanning usb for ethernet devices... 0 Ethernet Device(s) found
Hit any key to stop autoboot: 0
CL-SOM-iMX7 #`

Any suggestions?