Resistors, two ways to use them: EDL test points or eMMC defeat.
EDL: check with voltmeter (like you did already) for two adjacent points, one at 1.8V and one very near 0.0 (could measure higher/noisier 0.1 or whatever). You need a resistor 100 to 3000 ohm. Bridge the two points with it. Do a LONG power press. Use USB utilities to see if something appears/disappears.
Pointless note: If your device
was working and rooted I have a command line utility that will tell you if you've activated the EDL test points without having to do reset or anything. Shown: 2x activated.
Code:
Poke3:/ # /data/local/tmp/edlcheck
0 1 0 1 0 ^C
Poke3:/ #
eMMC defeat: You're trying to make the flash look like it isn't there. This is more difficult. You need a low value resistor 100-200 ohms. You are connecting the resistor between some random point somewhere near the eMMC chip (maybe a surface mount resistor) and ground. LONG power press.
Try the EDL first.