Thread: How to reduce the size of a gmapsupp.img file on a card???

Originally Posted by Butters

So, you can maybe now clearly see that 2 GB is 2,000,000,000 bytes but 2 GiB is 2,147,483,648 bytes. Also your so-called 2GB CF card only has effective storage available of ~1.90 GiB or 2,047,541,248 bytes. Your garmin-based GW Navi can actually read an image up to the FAT 16 file size limit which is one byte less than 2GiB or 2,147,483,647 bytes so by using a card larger than your 2GB CF you can get a slightly bigger img file on it, almost 100,000,000 bytes or ~10 MB larger in fact. If you have a later model GW with an SD card navi then your 2GB SDs have even less space than a CF.

This is assuming
1. There are no bad sectors that would give less space than the "theoretical" limit
2. Taken into account of overhead of the FAT table