I've installed TWRP v2.8.0.1 to both our Galaxy S3's (AT&T and Sprint). In both phones I can backup and restore Nandroids when saving to the internal sdcard. I can also backup to extsdcard (ie, it reports successful), but it fails MD5 check when attempting to restore from extsdcard. Google searches have provided no clues as to what the problem might be. I did verify that the sdcard is formatted with FAT32 in case that matters. None of the Nandroid files exceed the 4GB limit imposed by FAT32. Any help appreciated.