Got a G6 Real 16 last week, charged it overnight, transferred some games over, they wouldn't save. Formatted the card, transferred the latest System folder over again, same problem also half the time the games icons were corrupted.
Emailed Model-Gadget and they sent a replacement as soon as my original card arrived (took 5 days to arrive because of the postal strike backlog).
Charged the card for 12 hours in ds with power on at the mains.Updated with the latest System file from a day ago.
Same problem, games never, ever keep their save. Formatted, tried it from the DS and in windows explorer.
Same problem.
Model-Gadget said the last batch of G6 Real 16s were known to have a good few dodgy cards but this latest batch should be ok.
Obviously they are not so am going to email them in the morning and ask for either an Acekard, or Cyclo Evolution instead. Already have an R4 and am very happy with it.
My advice is to avoid the G6Real completely, my experience with it has been a huge waste of time and way too much hassle.
If you want a decent card look through the reviews and user comments here, basically get anything except this piece of rubbish.