Note: Backup all important data from your SD card to your computer.
requirements: USB SD Card reader.
Pull SD card from phone, insert into USB SD Card reader. Windows should report new drive and content of the drive should be visible.
Steps to Partition Android/Camera SD Card
1. Download and install Partition Wizard Home Edititon for Windows.
Note: this partition manager QUEUES the operations. So nothing is deleted and changed UNTIL you click "APPLY" and then confirm by clicking "OK".
Make sure you are deleting partition on SD card! (not your hard drive for example)
This step deletes everything on SD card, so backup files first!
Dont be afraid, just read everything and think twice before selecting correct drive.
Do you see three gray icons on the bottom? Under each of them the capacity of each drive is listed, and SD CARD has slightly different icon.
Hard drives on the screenshot have 465.8GB and 74.5GB, and on the bottom, the SD card, with 3.8GB capacity.
3. Create FAT or FAT32 partition select. "Create As": PRIMARY.
Select "File System:" FAT when you have 2GB or smaller card.
Select "File System:" FAT32 when you have 4GB or greater card.
4. Create ext2 or ext3 or swap partition*. "Create As": PRIMARY.
Select "File System:" ext2 - for App2SD
Select "File System:" swap to make swap.
If you want to create both: do not assign all the space for the first one :) this way you will have space for creating second one.
Finally, click "apply" button on top left corner. Partitions will be created and card will be formatted. (from：http://forum.xda-developers.com/wiki/SD_card_partitioning)
Note: The above steps can actually partition your SD card successfully, but it’s reported that not all the partitioned SD Card for some Android or other phone users. This problem may be caused by your phone built-in settings, the partitions can not be recognized by your phone. When you encounter this problem, you may refer to Gparted, which can also partition the SD card.