Spontaneous loss of NVMe and networking (Librem 14)

Hi folks, I have a bit of a strange one for you.
Been running Qubes on a Librem 14 for a year or more without incident. It’s my daily driver.
After a system lockup with no apparent cause (not doing anything difficult), the device now no longer detects the internal NVMe drive or the networking hardware (neither WiFi nor ethernet).
I’ve been able to boot using a PureOS live USB, and to connect to the network using USB tethering from my phone, but it’s as if the internal hardware is gone!
Running ‘fdisk -l’ or ‘blkid’ only shows the USB drive, and running ‘ip a’ shows only the USB network device. Running ‘lshw’ also only detects the USB network.
The led next to the WiFi kill switch comes on at initial power-on, but goes off part way through the boot process (without the switch being touched).

I opened the laptop and moved the NVMe drive to the second socket - no difference. I bought a new NVMe drive and the laptop doesn’t detect that either, suggesting the problem isn’t the drive.

I then disconnected both internal batteries for around half an hour and then restarted the device - no change. I’ve used the PureOS live system to update coreboot to the most recent version, which has not changed anything, so I’m at a loss as to how to proceed. Any suggestions would be most welcome!