Background Back when I got my GL-AR150 mini router, I was blown away by the powerful capabilities of this $25 OpenWRT router,...
Removing undeletable partitions on SD CardsStanislav Khromov
Sometimes Computer Management won’t let you use the entire SD Card. (By not letting you extend your primary partition.)
To fix this you need to clean the card up. Warning: It will erase the contents of your card.
Run the following in a cmd prompt:
diskpart list disk
At this point, find your SD Card. (Easiest to do by identifying its size.)
select disk X clean create partition primary active format fs=fat32 quick assign
(Where X is your SD Card drive.)