Lottery ticket X1 Carbon 6th gen - Can it be saved?

[mgeoffriau]

I picked up an X1 Carbon 6th gen a few days ago on the reddit thinkpad marketplace. It was advertised quite cheap, as-is with a Windows BSOD loop that the seller had been unable to resolve. I figured for the price, at worst I'd have a handful of parts I could resell, but maybe I'd get lucky and figure out the BSOD issue.

So far, I have not been lucky. The initial issue was pretty straightforward. Laptop would boot, the Windows 10 splash screen would display, the circle would spin for a moment or two, and then BSOD. If you let it reboot, it would get to the Preparing Automatic Repair screen, and then BSOD. Wash, rinse, repeat. The specific BSOD message varies, but is usually one of:

* SYSTEM SERVICE EXCEPTION (Wimfsf.sys)
* KMODE_EXCEPTION_NOT_HANDLED
* IRQL_NOT_LESS_OR_EQUAL
* 0xc000021a
* REFERENCE_BY_POINTER
* KERNEL_SECURITY_CHECK_FAILURE
* DRIVER_IRQL_NOT_LESS_OR_EQUAL (ACPI.sys)
* PAGE_FAULT_IN_NONPAGED_AREA

What I've tried so far:

* Run Hardware Diagnostic Check from boot menu - All components pass successfully, including CPU, memory, and storage.
* Boot from MemTest86 - 4 passes completed with zero errors.
* Boot from Windows Install/Repair USB - BSOD on the splash screen.
* Boot from Ubuntu 18.04 LTS USB - Kernel panic (see screenshots below).
* Boot from Slacko Puppy 6.3 x86 - Kernel panic (?), not sure what errors mean but assuming no bueno (see screenshots below).
* Removed NVMe SSD - Same BSOD/kernel panics.
* Removed wifi card - Same BSOD/kernel panics.
* Removed and reseated battery - Same BSOD/kernel panics. Didn't expect a battery issue but wanted to rule it out.
* Removed heatsink/fan assembly, replaced with fresh thermal paste - Same BSOD/kernel panics. Didn't expect a thermal issue but wanted to rule it out.
* Reset laptop with reset pinhole button - Same BSOD/kernel panics.
* Updated BIOS to latest 1.5.0 version - Same BSOD/kernel panics. Previous version was 1.4.9.

Screenshots here: https://imgur.com/a/x5761Nn

At this point, I'm running out of ideas. I thought about pulling the SSD, connecting it via USB adapter to another system, and seeing if I could pull the Windows dump file. But I'm not sure it's worth the bother, given that it's kernel panicking even when booting from Windows or Linux USB's.

Given the lack of success with the above attempts, this seems more like a hardware issue with the system board, but I honestly wish it would fail definitively during the Hardware Diagnostic Check or when running MemTest86 so I'd know for sure. All the replacement system boards I can find right now are $400-500 which is too big of a gamble for me, but if I knew replacing the system board would fix it, I'd hold onto it for a while to see if I can snag one more cheaply.

Any thoughts or suggestions on what else (if anything) I could try?

[axur-delmeria]

Reset BIOS settings?

Though to be honest, it seems like a processor issue. Could also be a RAM issue, as even memtest86+ can't find all types of RAM errors.

[RealBlackStuff]

Problem with such machines: nearly everything is soldered, incl. RAM.
That machine has 2 USB-ports, have you tried both?
Could one of them be faulty/broken?
Is it still under warranty?
With everything (except LCD/external monitor, keyboard and charger) removed, can you boot into BIOS?

[mgeoffriau]

Reset BIOS settings?

Good thought. I failed to mention it my original post, but BIOS settings have been set to default.

Problem with such machines: nearly everything is soldered, incl. RAM.That machine has 2 USB-ports, have you tried both?
Could one of them be faulty/broken?
Is it still under warranty?
With everything (except LCD/external monitor, keyboard and charger) removed, can you boot into BIOS?

Tried both USB ports, yes. No warranty. No problem booting into BIOS even with all peripherals still connected; it's only failing when attempting to load an OS.