I've a 16 GB MicroSD card that's apparently faking its size. Using H2testw I found that only the first 7.8 GB are usable. Before buying a new one, I want to see if I can "fix" it. The idea is to have Android format the card "as internal", unmount it, and then either through a rooted Android or a Linux/Windows desktop downsize the three resulting partitions to fit inside the first 7.8 GB of the card.
Is there any reason why this wouldn't work? My only concern is that the Android phone might have its own record of the sector ranges of each partition, which I would be changing.
I'm not just trying it out, because I don't have a card reader on hand, and want to find out if it's likely to work, before I invest time into it.