How to get the full amount of MicroSD memory. Instruction!

[SPARKRU]

In Android settings, you need to reset to factory settings. 

Or to do so - 
After you burn the image to your microSD, In order to be able to see the full volume of your microSD card in Android, 
I recommend that you boot into - Recovery mode and make Wipe Cache Partition and Wipe Data/Factory Reset. 

How to use recovery mode TB. Instruction!
Use this image https://fossbytes.com/wp-content/uploads/2018/01/asus-tinker-board-s-parts.jpg 
After turning on, you need to close the contacts for a few seconds - Power-on and eMMC Recovery.