Rolling back a system update can be complex, and I believe requires rooting. I don't know the process in detail.
There may be a specific file or files on the SD card that is corrupt (which wouldn't necessarily be caught by chkdsk, because a corrupt file doesn't necessarily mean a bad sector). Copying that file to the new card may have simply transferred the problem to the new card.
When you're removing your SD cards, are you unmounting them first in Settings>Storage? If you're just popping it out without unmounting, it might be causing corruption. If you remove it while the phone is powered off, that's ok.
09-03-2014 05:08 PM