How to create complete image backup(Nandroid) of rooted phone if no cwm or twrp available for my phone
Provided your device is rooted, you can do that with simple dd commands. Trouble is just to find out what partitions you might need to backup: some devices have more than 20 partitions, and you will most likely not need more than 5 backed up.

This is where e.g. my little tool Adebar comes in which, amongst others, creates you a script for exactly this purpose: dd the relevant partitions and get them to your computer, giving the files recognizable names. The result for my LG P880 e.g. looks like:


adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p3'" > "images/system.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p4'" > "images/cache.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p12'" > "images/cal.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p9'" > "images/persist-lg.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p11'" > "images/FOT.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p2'" > "images/LNX.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p10'" > "images/mpt.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p5'" > "images/MSC.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p7'" > "images/NVA.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p1'" > "images/SOS.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p8'" > "images/data.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p13'" > "images/UDB.img"
adb shell "su -c 'stty raw; cat /dev/block/mmcblk0p6'" > "images/USP.img"


As you can see, this does not only include partitions mounted at the time the script was generated, but also all other "named ones".

Adebar is plain Bash + ADB, and reportedly works in Cygwin (as well as of course on Linux).