Found this forum comment re the rebooting sequence fix...

"The LG G4, V10, and the Nexus 5X are all affected by the bonded flipchip substrate breaking off of the BGA package under the CPU, which usually manifests in bootlooping or screen corruption, and eventually a complete brick. It’s not solder related; the only way to fix it is by completely replacing the CPU package with one that isn’t defective. – FrankTheCat"

..alot of work for a little action. Got the phone to boot after heating the CPU for 15sec, stayed on for 4 minutes before rebooting again. ~sigh~

This is an age old fix for crappy solder points connecting to CPUs or GPUs (most notably in HP laptops). Disassemble the phone and heat the snapdragon chip with a heat gun for 10 seconds. The chip is beneath a metal shield that pops up with a flat screwdriver. I am working to complete this now.. .will let you know how it works.

in most 'google image boot' issues, it is a hardware issue, not software. besides, the phone will not allow a bootloader option.

Don't worry about learning, because it is a hardware issue, not software. The phone will not boot proper past the fastboot.

yes, open from bottom first... the pic above shows the finished product after reaching top of phone. I found it best to actually start close to the right of the usbC connector. Pushing inbetween the 2 tabs and up will release the shell.. then work clockwise.