Erased windows partition by Diskutility still can see the EFI boot on the boot screen

This the setup i had
iMac 21 inch
HDD for (500GB) for OSX installation
SSD for (256GB) for windows 10 installation

This was working perfectly, until I upgraded to OSX High sierra.

After updating to High sierra, OSX stuck at the booting process and shows the spinning wheel all the time. therefore I used the recovery mode and re-installed high sierra again but no luck. During that time I have erased the windows 10 SSD via diskutlity as well.

Then I used the time machine back up (2 year old) and reinstalled OSX EI Captain. afte 3 and half hour installation process, it booted and shows the white screen with the cursor. I tried with safe mode it worked, but when I use normal mode it didnt. Then I followed these setps
1) Try to Reset the NVPRM, in the restart process windows BSOD came up and displays the recovery options.but in startup disk was set to Macintosh HD.
2) Then used the Internet recovery and opened the terminal and typed the diskutil list it shows disk0 as windows partition and disk1 as Macintosh , disk2 as recovery partition.
But i can see partition until 20 with each having 1 MB allocated space. I can send you the screen shot if you want.

Checked the diskutils CS list, its shows no corestorage logical volume groups found

Now I am running out of idea about how to recover the system back. struggling last two weeks.
I have created the latest image of the Macintosh HD before using the Internet recovery therefore not worrying about data loss.