typically you’d restore from a recent snapshot that you saved somewhere else - no different from your flash storage dying other than you don’t need new hardware to fix it.
Alternatively, I’m guessing you could try doing some piecemeal recovery using a Linux system.
I had this too - it may have been caused by running out of disk space.
I had to totally re-image the Blue.
My snapshots were only on Blue - lesson learned.
I do feel that as a target platform for less experienced users it would be nice if this could be protected against.
I backup to google so all is OK for a restore. I was hoping to avoid it if I could.
Ive been playing with trying to mount the mmcblk0 partitions to see if I could clear some space…no luck with that apart from access hassos-boot.