How do I use EasyBCD as bootloader with Windows 8 and UEFI?

First, the last I heard, EasyBCD was useless for managing a Windows/Linux dual-boot on an EFI-based computer, so I recommend you stop trying to use it.

Second, given your current situation (as specified in your Update), there are several possible solutions. The two easiest are:

• Run Boot Repair. I know you said you've tried this, but it's not clear if you've tried it since the change to the situation in which you can boot Ubuntu but not Windows. If not, it's worth trying Boot Repair again.
• Install my rEFInd boot manager. Installing the Debian package in Ubuntu is the easiest way to do this, although it's a bit safer to try to use the CD-R or USB flash drive version first, and install the Debian package only if the CD-R/USB flash drive version can boot both your OSes. rEFInd is less finicky about booting Windows than is GRUB, so it might fix the problem.

If neither of these methods fixes your problem, please post back with a fresh URL for your latest Boot Repair run.

Update: First, be sure that Secure Boot is disabled.

Next, are you able to boot via the rEFInd USB flash drive or CD-R image? If so, try this:

1. Boot to Linux.
2. Open a Terminal window.
3. In the Terminal, type sudo efibootmgr to find all your current boot entries.
4. In the Terminal, type sudo efibootmgr -b 0000 -B. This deletes the Boot0000 entry.
5. Repeat step #4, replacing 0000 with each Boot#### number identified in step #3. (Your Boot Repair output suggests you'll have 0000, 0001, 0002, 0004, 0005, 0007, 0008, 2001, 2002, and 2003.
6. Type sudo efibootmgr -c -p 2 -l "\EFI\ubuntu\grubx64.efi" -L "Ubuntu". Note the backslashes used as directory separators.
7. If you've installed rEFInd to the hard disk after running the last Boot Repair, type sudo efibootmgr -c -p 2 -l "\EFI\refind\refind_x64.efi" -L "rEFInd".
8. Reboot.

If all goes well, rEFInd should pop up, or at least GRUB, and you should be able to boot both Linux and Windows.

If the rEFInd CD-R or USB flash drive doesn't work, you could try the same from a Linux live CD that's booted in EFI mode.