How can I merge partitions of a USB flash drive?

Solution 1:

If it's one of those silly* U3 flash drives where one piece masquerades as a CD-RW, you will need to run the uninstaller to remove that partition.

*silly because it's amazing how much malware you can cram into that CD-RW piece and autorun will happily execute it because it's supposed to be a CD-ROM drive.

Solution 2:

See this discussion. It covers, among other things, getting the flash drive recognized so you can fdisk it.

Solution 3:

Some flash drives appear as two partitions because, internally, they are literally two separate devices.

Older flash drives, or cheaper units, might use a memory controller that can only address X memory, but the manufacturer wants to provide a device of 2X capacity. Each controller is detected by Windows as a separate drive of X size.

On such a device there is no way to repartition and make Windows see it as one single partition of 2X size. Doing so would require physically hacking the device, and replacing the multiple cheapie controllers with one controller that could address all the memory at once.