use mini tool partition wizard
1. connect ur sd card to pc.
2.launch mini tool partition wizard.
3.select ur sd card and right click
4 . delete all partitions.
5. finally create a single partition..
1.Connect your sd card to your windows pc
2.Open mini tool partition wizard
Find a option to "fill all zeroes" or "fill all ones"
3.Wait until complete(takes more time - be patient)
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