Creating Custoom ROM file

[AC Question]

I have rooted successfully my Samsung Galaxy S7.
Now i would like to backup the Firmwave to a file and implement it on secondery device using Odin.

i try to create the ROM file (tar file) that contains:

/dev/block/sda5 (BOOT)
/dev/block/sda6 (Recovery)
/dev/block/sda14 (SYSTEM)

i use dd command to copy it and to rename it as:
factoryfs.rfs (BOOT)
recovery.bin (Recovery)
zImage (SYSTEM)

without the brackets.
u created tar file and md5 using:

tar -H ustar -c factoryfs.rfs recovery.bin zImage > package_name.tar
md5sum -t package_name.tar >> package_name.tar
mv package_name.tar package_name.tar.md5

When i try to Flash it using Odin it's stuck forever.. i think it's happen because the file names are not correctly for the S7.
Please help me!