请教各位高手：如何格式化2G SD Card(SanDisk)？

I tried first to format it using command "format E: /FS:FAT" and it was formatted to 2G. I can read files from my PC but it won't work for my iPAQ. Then I formatted it using my iPAQ and it was formatted as 1G. How can I format it back to 2G? Thanks a million!