Complex sentence: Versions 3.3 and 3.4 of the Wii Menu prevented copying exploited save files until circumvention methods were discovered, and version 4.0 of the Wii Menu patched the vulnerability.
Split into simpler sentences: Versions 3.3 and 3.4 of the Wii Menu initially prevented copying of exploited save files until circumvention methods were discovered. Version 4.0 of the Wii Menu patched the vulnerability.