There're many ways of copying out the linux root filesystem. The easy way, is using rkflashkit or alike to backup the linuxroot partition
Another way, is copying out the files in linuxroot, by mounting a SD card/usb disk etc: a. Insert your sd card/usb disk.
b. Check the path (usually under /media/firefly), and cd into that. $ cd /media/firefly/your_sd_card
c. Check your rootfs's size: $ sudo du -hxs /
1.8G /
d. Create the ext4fs image file: $ sudo dd if=/dev/zero of=new_ubuntu.img bs=1M count=2000 $ sudo mkfs.ext4 -m0 new_ubuntu.img NOTE: 1. bs * count should be greater than your size of root partition (add about 200~300M for extra space) 2. If you're using the vfat filesystem in the sdcard, the vfat has a file limit of 4GiB bytes.
c. Mount the image file: $ sudo mkdir -p /mnt/new $ sudo mount -o loop new_ubuntu.img /mnt/new
d. Copy files: $ sudo cp -ax / /mnt/new/
e. Umount the image file: $ sudo umount /mnt/new
Now your root files are copied into new_ubuntu.img, which can be flashed back later on. And the first time you flashed the image back, you'd better run a resize2fs on the linuxroot partition: $ sudo resize2fs /dev/block/mtd/by-name/system |