I encountered this problem and somewhere found a suggestion to remove the external SD card and found that substantially helped. I would power-off my tablet, remove the SD card, power-on the tablet, update iFlyGPS charts, power-off the tablet, re-install the SD card, and would be good to go.
I recently ran into an issue where I was getting a report of out-dated charts while using my tablet, despite having followed this proceedure to update my charts. Here's how I resolved that and simultaneously re-enabled direct download of charts without the SD-card removal work-around proceedure.
- With the tablet powered off, remove the SD card, and replace it with a blank SD card (doesn't have to be big, this is a temporary use).
- Power on the tablet, start up iFlyGPS this will likely involve a long wait as it recognizes the new SD card and integrates it for use
- in iFlyGPS select "Check for Updates" and select "Advanced Options": Then configure "Storage Location" to be "Internal"
- Exit and power-off, then replace the SD Card with your original SD Card which still has all your glorious music and movies on it
- Now iFlyGPS should download updates without issue with SD Card still installed (at least it did for me)
No guarantees, I'm not a developer, just a user who found a work-around that works for me. (Yeah the twenty years of experience doing hardware debug might have helped a little.) Hopefully it works for others.