As boards may have no jtag port, the internal usdhc4 root clock out needs to be remapped. When “CUP not initialized” issue has been seen and in download mode, DDR test tools can be used with the script to remap clock output.
Please check the attached for test script and the empty the binary. Put the two files to DDR stress test tool folder “DDR_Stress_Tester\binary\”. The attached ddr-stress-test-mx6dq.bin is an empty file. Please backup the original file first. After eMMC boot failed and in download mode, run command “DDR_Stress_Tester.exe -t mx6x -df test.inc” on PC side. There is no clock output on GPIO19. For normal test, please erase the eMMC chip and boot the board. It will also fail to boot and run into download mode. After run “DDR_Stress_Tester.exe -t mx6x -df test.inc” , clock can be measured from GPIO19 if no PDF issue happens.
And for the normal boot, erase the emmc, and reboot to enter the download mode. There will be no signal output but high voltage on R112. After the script runs, 40Mhz clock will be seen. For the boot fail case, there will be no signal output but high voltage on R112 and 40Mhz clock will be pulled to low.