Permission denied for “dd” of Android phone's file system connected over mtpfs in Ubunutu 14.0.4
Short answer: a complete copy of your phone over dd can't be done.

Explanation: Normally when you access a file, your file system driver will parse the folder hierarchy, translate it to an inode, locate the sector on which the file is stored, the metadata is parsed and the file is read. MTP does things differently: your computer sends a request to the device to get file X, your device will parse the directory structure, parse the metadata, locate the sector/cell on the storage device, read the file and then send the data back over MTP.

dd will make a copy of the blocks that are on the storage device itself. Therefore you can copy files and entire partitions because they are blocks of data on the disk. Directories are stored on the disk but they aren't real regions of disk space, they're more like references so files can indicate "I'm part of this folder". Therefore you cannot do a block copy of a directory. Because you cannot do a block copy of a directory, copying the entire storage device of your Android phone over MTP is not possible.

But there is hope: if your device software allows it, you might be able to mount your device as a USB storage device. This will directly attach the storage partition to your computer, allowing you to make a backup using a command like dd if=/dev/sdb of=~/backup_file.

Alternatively, because you have root you could enable Developer Mode on your Android device and then execute the following command after installing the ADB tools (sudo apt-get install android-tools-adb):

adb shell su -c "dd if=/dev/block/mmcblk0" &gt; ~/full_phone_backup.image


This will make a copy of everything on the storage device. It will run for quite some time. I never reached more than 20MB/s over ADB, so it would take 64000/20=3200 seconds at max speed to copy a 64GiB device. After the copy has finished you can run your file recovery software over full_phone_backup.image to get any files back from the system.