Open the "NAND.BIN" backup file you made with HxD software and see the line 00000100.
You must have "NCSD" word in the right column.
Is it the case ?
Could you make quick video to show me the start of the console to estimate the delay to get BSOD ?
Need to see when you push POWER button and screen in the same time.
Thanks.
PS : If you have a multimeter, test black wire (GND) and green wire (DAT0) to be sure you have no contact between them.
IMPORTANT: The lenght of wires must be equal or less than 25 cm !!! If too longer, the NAND can't be detected by computer.