Flashing

• A - Automatically Trim When Flashing: With this option checked, games will have the excess unused data from the game stripped from it. This is a great way to save space for storing more files on your flash card, as most games do not use the entire amount of space that the file is created in. For example, my Super Mario 64 DS game backed up as a 16MB game, however once the excess fat from the game was removed by trimming it, the filesize came to 15.5MB. Some games don’t trim as they use the full size of the card, and some trim a lot. It adds up and you can definitely store more with trimmed files.
• B - Use “Safe Trimming” Method: This should be used with any games that support WiFi or DS Download Play. It will preserve the extra space at the end of the game data to allow these features of the game to work. As a safety measure, it is most likely best to always have this enabled if you are enabling trimming, but hey you’ve got the option!