• Download the latest Linux For Tegra (L4T) package from here and unzip it

• Open a terminal and change to the following directory: linux4tegra/nvflash
  

• the following command sends the vanilla bootloader into your device RAM (it will not overwrite anything)
  # LD_LIBRARY_PATH=. ./nvflash --bl ../prebuilt/fastboot.stock.bin --go

• the following command saves your disk partitioning (very important!)
  # LD_LIBRARY_PATH=. ./nvflash -r --getpartitiontable partitiontable.txt

• use the following command with to save the partitions one by one to your harddisk (see Partition Layout for details)
  # for i in $(seq 2 14); do LD_LIBRARY_PATH=. ./nvflash -r --read $i part-$i.img; done
  
  You should endup with part-2.img, part-3.img [...] up to part-14.img, and partitiontable.txt.
  Keep them in a safe place if you intend to play a bit with your AC100.
  

• In the partitiontable.txt, you should see following pattern (you need the highlighted values for each partition you want to restore):
  
  PartitionId=[PartitionId]
  Name=...
  DeviceId=18
  StartSector=[StartSector]
  NumSectors=[NumSectors]
  BytesPerSector=2048

• Open a terminal and change to the following directory: linux4tegra/nvflash

• Reload the vanilla bootloader using the following command:
  # LD_LIBRARY_PATH=. ./nvflash --bl fastboot.bin --go

• For earch part-[PartitionId].img you want to restore, execute the following command:
  # LD_LIBRARY_PATH=. ./nvflash -r --rawdevicewrite [StartSector] [NumSectors] part-[PartitionId].img

• Reboot your device.

Easily Backing up and Restoring with AC100 Toolkit

• It automatically downloads and installs nvflash for you.
  
• It can backup all your partitions with two simple commands.
  
• Restoring your partitions also becomes easier.