I have previously written the Debian image to a 4GB SD card. Now I wanted to write the newer 2012-04-19 image. But win32disk imager complains about not enough space. I notice that only a single 128MB partition is visible to Windows. How can I clear the SD card to show it's full 4GB storage again thus allowing me to write the newer image.
I've tried the SDFormatter 3.1 tool, but that will only format the 128MB partition as well.