Michael,
The iFly 520 can be updated with a USB thumbdrive as well as using iFly Connect on a PC or saving the iFlyUpdatePackage.zip file directly to the SD card. The optimal way is with iFly Connect, however if that is not possible, then I'd download the zip file to the SD card. Safari is a bit tricky as it will try to unzip or "Open Safe" files after download. You can turn this off inside Safari Preferences on the General tab.
It sounds as though your chart updated, I'd suggest double checking the Software and Databases. Also, keep in mind it adding the update package to the SD card, I'd recommend keeping it smaller and free space is limited. IE, make one update with Software and Databases, then do another for VFR and another for IFR.
I hope this helps. Feel free to contact our Support Department at 888-200-5129, press option 1 and they can help you out.