We have a custom board used the i.MX6 DualLite and now we can't boot from SD successful. We even can't measure SD_CLK signal.
We tried to change boot mode to serial downloader mode, and use stress test tool v2.52 to read SRC_SBMR1 which value is 0x00000000 and SRC_SBMR2 which value is 0x00000001. The SRC_SBMR2 value is very strange, we have set boot mode to serial downloader mode, bit 24-25 should be 0x01, but when we read it, it 0x00.
We have check all BOOT_CFG pins are right, and follow "Hardware Development Guide for i.MX 6Quad, 6Dual, 6DualLite, 6Solo Families of Applications Processors" chapter 2 and chapter 8, measured the power on sequence, power rail and clock, they all seem OK.
Could you give us some ideas?