Suddenly Unable to Boot

[y-nought]

Win11 seemed fine for a while, but then just went away of its own accord (nothing running on it at the time) and I now get (when viewing direct mode):

BdsDxe: loading Boot0001 "UEFI Misc Device" from PciRoot (0x0) /Pci (0x7,0x0)
BdsDxe: starting Boot0001 "UEFI Misc Device" from PciRoot (0x0) /Pci (0x7,0x0)

...which hangs for about a minute and then just disappears.

Any ideas on how to recover, or is it a total loss?

If it's relevant, I've tried reenabling USB passthru (which was previously working) but it fails to find it (message precedes above). It does try to load it, as it disappears from the pi desktop while it's trying to boot.