The last week was far from the best time of my life.
I was unable to confirm that the underlying SSD or HDD drives were having any issues. I don't know why Bcache got corrupted all of a sudden, making my root Btrfs filesystem unbootable as well. I've had a 2-months old backup of the root partition (when I moved my Btrfs filesystem to Bcache). No project data was lost, I had that on an a separate drive, on another Btrfs filesystem. And also I do incremental backups of that ever day. If you want to learn why installing Arch Linux took me 3 days, here's a forum thread I've started when I got stuck: https://bbs.archlinux.org/viewtopic.php?id=271206 Going forward I'll make better better backups to recover quickly from such failures.