Ideapad S340 with Ubuntu+Win10 in dual boot mode

The above solution worked. I am now able to use the Ubuntu 18.04 USB and see both SSD and HDD using gparted and disks. Win file manager could copy and rename the .efi file as recommended in this link. Ubuntu file manager had some permissions/read-only issues.

Closing this post as Solved, with a final round of sincere thanks to @OstroL.

A post was split to a new topic: Windows not booting up after playing around with registry and UEFI