Tar and other file archiver may miss some specific file attributes and special files. At least for ext2/3/4 file systems, old fashion BSD dump and restore utilities (debian package simply named dump) remains a perfect solution to backup an entire file system. The following procedure may help to move a filesystem from a disk to another.

• backup root filesystem to a file. Beware! Avoid to put the backup file on the filesystem to be dumped:

# dump -0z -f /mnt/backup/rootfs.dump.gz

• to restore the filesystem, first create a new fresh partition and empty file system (fdisk + mkfs). Then use restore command to unpack the dump file into the new file system.

# cd /mnt/newfs
# restore -f /mnt/backup/rootfs.dump.gz

Read more Dump and restore full file system

Since mass storage device is not always available, exchange files using MTP becomes mandatory.

• 1st, install jmtpfs package or simular (mtpfs, go-mtpfs). fuse is needed.
• add users that need to mount such device to the fuse group.
• create a new directory that will be used as mount point (for instance ~/mtpdev).
• For each file exchange session:
  • plug your USB device (beware, connection some android phone will fail if in standby mode, unlock your device first).
  • mount device: $ jmtpfs ~/mtpdev
  • do wathever you want on the mounted file system (unfortunately, much slower than any mass storage device).
  • Once all exchanges are completed, unmount file system: $ fuser -u ~/mtpdev
  • The device is ready to unplug.

Read more Mount MTP USB device

$ modprobe usbnet
$ ifconfig usb0 up
$ dhclient usb0

Read more Use an android phone as internet gateway