I guess we could try to fine tune our interventions but I suspect the phone does have the issue I already quoted Resurrecting a bootlooped Nexus 5X | tony is coding.
The manufacturing issue involved has its own Wikipedia page LG smartphone bootloop issues - Wikipedia
- LG stated that it was caused by a “loose contact between components”
- Android Authority explained that "a loose connection between power supply or memory components could certainly cause a phone to fail to boot up properly, due to a lack of system stability or not being able to access vital memory.
- This could be down to important setup communications not being sent or received between peripherals correctly.
- Nexus 5X In September 2016, reports began to circulate that similar failures were being encountered with the Nexus 5X manufactured for Google by LG, particularly whilst upgrading to Android 7.0 “Nougat”
The above has also been called Bootloop of Death (BLOD). There is an XDA tool to try to fix it https://xdaforums.com/t/tool-how-to-nexus-5x-bootloop-of-death-blod-workaround-flashable-zip.3819497/.
It amounts to a two stage job,
- a special (reduced load) TWRP
twrp-3-2-1-0-fbe-4core-bullhead-img - then flashing AnyKernel3 zip via TWRP.
One then hopes that the Stock ROM will boot. It is noted
- Reflashing the BLOD AK3 zip will likely be required after anything that could modify the boot.img or recovery.img, including (but not limited to): ROM updates, custom kernel updates, custom recovery updates.