[Google Pixel 2 XL Questions & Answers] simplepinoi177:
OMG [MENTION=8845092]Coolpente[/MENTION]!!!! THIS....HAPPENED...TO....

ME

!!!!

Holy crap! I can't believe this happened to someone else! I thought it was just me and my bad luck!

I literally was doing the same thing (only difference was on my gf's pixel 2 [walleye])! And those who have seen me around this forum the last year know that I am very knowledgeable and don't make the simple and "noob" mistakes! I've literally have helped and recovered people in this/our position -- so it is doubtful there was a amateur or novice mistake made in the updating process or "stone un-turned" in the recovery process!

So here is what happened to me, particularly, and my observations on it...

- When "crap hit the fan", it was very peculiar that fastboot would identify the phone's serial number as "??????????" (when running the command "fastboot devices"). Only after rebooting and disconnecting/reconnecting the usb cable did it (fastboot) simply just stop detecting. To make sure that my computer, usb port, cable, and fastboot is working correctly and able to process properly, I would make sure the fastboot process/server was not running, then I would actually run the command "fastboot getvar all", and as it would "would for device", I would plug in the phone, nothing would happen, then plug in my phone [taimen] (not my gf's walleye), and it would detect it and display all the pertinent information and device details, I would then unplug it from my phone, run the same getvar command, and lastly replug it into the phone (broken gf's walleye) with no detection or success.

- What's also interesting and of note is that when loading straight into the bootloader (via button combination), it displays no error in the list of device details. But when booting into the recovery (note: I, like the OP, had the TWRP custom recovery already flashed and installed) and also the system and/or from a power-off state, it states in red colored font and yellow background, "ERROR: Slot Unbootable: Load Error". Even more than that is when attempting to boot into Download mode, it states a different error (but in the same font style), "ERROR: Operation Denied"!

- I also attempted to manually change the slot in attempts to address the "slot unbootable..." "...load[ing] error", but -- due to either fastboot not detecting or the device not connecting properly I imagine -- without fastboot properly detecting, the commands wouldn't work and execute properly anyway. I've even taken steps further and attempted to format and custom "re-size" partitions. But, for the aforementioned reasons (presumably), it and attempts at commands like it wouldn't likely work and execute, again as previously reasoned. Also, in attempt to tackle the "slot" aspect of the issue, I tried Deuce's script; but as Deuce's script is, simply put, based off of the flash-all.bat that ends up being an advanced batch (pun intended) of commands that manually and individually flashes the stock images/partitions to the partitions of the device -- so, in essence, uses fastboot and since fastboot can't work.... I even found and attempted to use the (hardly heard of; at least to me) tool Skipsoft Android Toolkit (which looks genuinely super dooper awesome btw...)... all for naught :crying: ...

You know, after a year with the Pixel 2 (XL), and after coming back from messing my phone up (15+ times), and actually purely bricking it once (had to get it replaced), I always thought that, as long as one could access the device via the bootloader, one would always have hope (at least in the Pixel's case). So, it's curious but agonizingly ironic being able to access the bootloader (which was not the case in my one and only instance of bricking my device and having a completely "lost cause") just for me not to be able to do anything about it and/or fastboot to not be able to properly connect and send commands to it...

But to me and Coolpente (and anyone else who this may have happened to) I ultimately can't think of anything else that can be done at this point. To re-iterate, I/we had the most up-to-date platform-tools (r28.0.1), it has been proven that the usb cord, port, computer, and drivers are all working as I was able to get the "getvar all" command to work on another pixel mere seconds before attempting the same on this (broken) device, and even attempted all tools available...

Unfortunately, [MENTION=8845092]Coolpente[/MENTION], it does look as if our phones are irrevocably "bricked" and it's all rather doomed and attempting to get it repaired/replaced by the manufacturer ("The Big G") is the only recourse we may have :(:(:crying::crying::crying:

I wrote this (very long) post in hopes of giving as much information and details as possible in the desperate hopes that any other solutions might be brought up...