Here I explain another way for those who have Windows OS beside the linux OS on the same machine.All of these steps are done in Virtual machine and it doesn't have any effect on your physical drives. First I give a summery to show the main idea and then I give more details.
1-In the Windows environment, create a backup of your linux EX4 partition.You can use any available backup software.(Here I used Acronis True Image 2016)
2-Create a new virtual machine in Vmware and start recovering process using the backup that you've created in previous section.
3-After doing recovery, you have the same Linux partition in your new virtual machine. Now to enable booting, you need to repair the Linux Grub which is capable of booting your system....And its done!
Some Details for implementation:
In the case of using "Acronis True Image 2016", these notes will be helpful.
1-When your are going to create a new virtual machine in Vmware, you should add "tow" hard drives for it.One hard drive must have "physical" access to your external HDD which your backup resides there.Another one must be the "virtual drive" and must be a little bigger than your Ex4 Linux partition.
2-For doing recovery process in boot, Acronis Gives you a rescue disk. Use this rescue disk in Vmware and boot the virtual system.
3-Because the virtual HDD that Vmware gives your is Raw, it is not accessible in Acronis rescue boot menu. So before starting recovery , you must create an EX4 partition from "add new disk" menu in rescue disk boot menu.
4-After doing the recovery process, you will have the exact copy of Linux EX4 partition in your VM.Now For Enable booting, use a Ubuntu live Disk for Repairing boot menu. To do so you can use this link.this link.