I can get into the bootloader (u-boot) and the kernel seems to be loading fine, so i have to imagine the sd card itself is fine, and is connected correctly on the board, but I keep getting stuck on the message "Waiting for root device /dev/mmcblk0p2".
I know that's the right device and partition; the sd card is connected to sdhc port 1, and the file system is indeed on partition 2. The only thing I can figure is that something must be messed up in my bootcfg resistors.
The 3 hardware boot port settings are: bootcfg4 = 0x00, bootcfg2 = 00000000 ; bootcfg1 = 01010010. The latter sets the boot device as: SD card, fast boot, normal SD speed, SD power cycle enable via SD pad, and SD loopback clock source via SD pad.
I pretty much followed the i.mx6ull evk board schematic (I'm told the i.mx6ull is pin- and software-compatible with the i.mx6ul, aside from a couple of peripherals i'm not using).
Could it be something in the device tree related to the SD card? I didn't touch anything in the "&usdhc1" section of imx6ul-14x14-evk.dts