2015-05-07, 04:39
I had a situation where my overlays folder had become corrupt (I had a file called "FSCK0000.REC" that looked like the contents of the overlays directory) and produced the same error in vcdbg. I'd suggest renaming or removing the overlays folder from the first Pi, then re-upgrading to #0506 so that a new overlays folder is copied over. Then see if you have a working sdhost.