Creating a multipartition bootable SDcard manually I'm trying to create a bootable sd card for an embedded board from Android images for various partitions (bootloader.imx, boot.img, recovery.img, and so on). Each of these images has to be written to specific partitions on the sd card with various filesystem types. Using a traditional disk copying programs like Win32DiskImager only allows to write to the whole disk at a time. I can use dd to write the images to the partition, but I'm not sure how to actually create the partitions on the sd card which range in size from ~1 MB (for the bootloader) to ~800 MB for the system image

Is there a way to create these partitions (with size and offset information) and write individual .img files to each of these partitions? Thanks in advance for any help.
I recommend you to take a look at parted or gdisk tool for this. It allows to create partition from specific sector with desired size. Then you can use dd command to copy the .img into these partitions. 

If you are looking for an partition app. for rooted device, you can try parted4android.  Disclaimer: I'm the dev.