"It appears the SD flash card is the culprit."

Not the physical memory itself, but the interface to it...GoPro can be named for any of the following infringement reasons: how the flash is managed by micro-controller / control circuitry; how the flash is formatted for use; how the flash bad memory issues are handled; how audio/video applications function; file management functions; audio filtering functions (dual mic); data I/O method...

for starters..

doni