[Google Pixel 4 Questions & Answers] flame-failure:
I bought a new Google Pixel 4 and it died within a week.

Installing the latest stock LineageOS went smoothly and everything was great for one week. While I was on vacation I pulled it out of my bag to take a photo and it had the overheating warning on the screen (it was in a bag on a cloudy and windy day, not in the sun, no background apps running). Not thinking much of it, I just shut it down via the normal procedure (hold power button, tap shut down) to let it cool and put it back in the bag to use again later. Because it was not in the sun or exposed to heat, I'm convinced that the phone itself spontaneously produced all this heat.

Now I can't get it to boot. This phone was brand new and is in pristine condition with absolutely zero abuse. Just one week of very light usage. No drops, no moisture, etc.

I disassembled it and re-seated all of the ribbon cables with no success. I have tried every button combination and duration with no results, as well as letting it charge overnight. I have tried the original factory charger and cable as well as an Anker USB-C charger. I cannot get anything to appear on the screen like the bootloader menu (with one exception mentioned below).

I do have a few signs of life, however:

When I plug it in, it warms up like it's charging

When plugged in and I put my ear to the charger, I can hold power + volume down for 10 seconds and the faint audible whine of the charger blips and bloops and changes momentarily like the phone successfully rebooted and it's renegotiating the power delivery

When I let it charge and then unplug it, the phone remains warm for hours afterward, leading me to believe it's alive and stuck in a boot loop or something

Here's the interesting part:

I let the battery die completely (no longer warm), then popped it in the freezer for a few hours. I can then take it out and quickly plug it into the charger. For a very brief moment (~1 second) I get the pre-OS

battery with lightning bolt symbol

on the screen that you get when you plug in the phone when it's powered off. Then the screen remains black and I can't get it to show me anything else, but it will get warm after charging as described above.

Thinking that maybe the battery was weak, I unplugged the battery ribbon cable and did the same procedure. I can leave it in the freezer and then quickly plug it in and then I will get a pre-OS

battery with question mark symbol

on the screen for the same brief time. This only happens once. Unplugging the phone and plugging it back in does not give me the symbol again unless I repeat the freezer procedure.

My conclusions:

There's nothing wrong with the screen since I can get an image

There's probably nothing wrong with the battery (it held a good charge when the phone was working), because with the battery unplugged I would be able to see the

battery with question mark symbol

for more than one second

While the phone is warm and supposedly running I don't get any sign of USB communication when I run lsusb.

Do I have any hope? What else can I try? At this point I don't even care about the phone, I really would just like to get my vacation photos off it.