"Default Boot Device Missing"---but no BIOS upgrade?

I happily ran my Batch 4 DIY laptop with Debian from last fall to last Friday. When I attempted to restore from hibernation on Friday, I got the “Default Boot Device Missing or Boot Failed” error; I fixed by reinstalling GRUB from a liveusb.

Altogether the symptoms are very much like [Solved]"Default Boot Device Missing" after update to BIOS 3.07, but—and here’s the kicker—I’ve never updated the BIOS. dmidecode shows
BIOS Information
Vendor: INSYDE Corp.
Version: 03.02

This is a little concerning. Anybody have any idea what happened? (Is there some way I could’ve unintentionally updated the BIOS, and dmidecode is giving me bad information? This doesn’t seem so likely…)

What SSD do you have? Some of the WD Blacks need a firmware update to work properly with the framework laptop, or else they can fail to wake from sleep state properly and cause exactly this error.

If you are using an WD_BLACK SN850, this article may apply to you: My system is rebooting to a “Default Boot Device Missing or Boot Failed” message.

Should’ve mentioned—I’ve got an SN750. Does that still require a firmware upgrade?

Maybe. Worth a try.

I’ll think about it—but my laptop’s working right now, and I’m a little nervous about messing with it.