Unable to duplicate a SD card with uboot/root/data

[g__]

I have a working sd card with 3 partitions (uboot / root / data) for an iMX 28 system. 

I would like to duplicate the sd to another one. 

I tried with several tools  (Win32 Disk Imager, ...) but it's not booting. 

What's the right way to do it ? 

Thanks

[qiang_li-mpu_se · Accepted solution]

You can dump the sd card on Linux PC or linux virtual machine:

sudo dd if=/dev/sdx of=~/dump.sdcard

Create the new card from the image:

sudo dd if=~/dump.sdcard of=/dev/sdx