Boot recovery is a strange critter. When my receiver did it, I was unaware of what it was. Because I kept messing with it, I delayed my boot recovery by well over 12 hours. Every time I messed with it, it started over from scratch. Personally, I'd leave it completely alone, don't touch it at all, make sure it has good cooling, and it hopefully will fix itself. Once mine finally came back, it was completely normal, and I had all my recordings.
IF yours doesn't recover in 24 hours, THEN I'd say it's gone for good.
IF yours doesn't recover in 24 hours, THEN I'd say it's gone for good.