Otherwise you can enable the test signing but if this is the only unsigned driver that you're planning on using then that probably not the easiest or best way of doing things (you'll need to include and sign a .cat for the .inf and the run the bcdedit -set TESTSIGNING ON to load the drivers). If you are using lots of older or unsigned drivers then you might want to set up your computer to always allow test signing. DSEO won't allow you to go into test mode but it's signing functions seem to work fine with Windows 8.1.

EDIT: There are also experimental linux drivers available. Last I saw they were incomplete but that's an avenue worth looking into. A linux VM could be exceptionally small (Damn Small Linux is about 50MB) and you could further strip any software you don't plan on using, turning it into an environment designed purely for interacting with EMS carts.

DOUBLE EDIT: Looking at the EMS Flasher for Mac / Linux, it should be possible to port over to a Windows machine given an install of Cygwin, as it should run on any system with libusb.

Any real options?

Bumping this like crazy. Could someone please try either of the things I was recommending to see if they make any difference?

I would but due to being a distracted impatient dork I wiped my Win8 install while playing with Ubuntu Studio.  I'll gladly check anything you need in 64bit Linux if needed?  My EMS carts have been largely ignored since I no longer have an XP or even Windows install on my machines.

Disabling driver signature enforcement *should* still work on Windows 8, just not through DSEO. Use thi to do it manually instead "bcdedit -set TESTSIGNING ON"
However, 1) you need to do it from an administrator command prompt 2) you still need to sign the driver manually.

Otherwise, try my other bcdedit line and see if that makes the boot menu show up at boot time. (You can even put a value of 10 just for testing since yo can change it later.) This should definitely allow you to press F8 on boot, which should simplify the process at least a little. Again, you need to do this from an administrator/elevated command prompt window.
Look here to see how to open an elevated command prompt: http://pcsupport.about.com/od/windows-8 … dows-8.htm

One of these days I need to install Windows 8 so I can try these things directly and don't have to rely on other people's sources, though.

Edit: Note that disabling signature checks, and enabling test mode are two different things. Disabling signature checks completely is considered dangerous because any application can now load kernel drivers, so it needs to be done at boot time every time you boot. All the timeout line does (hopefully) is allow you to get into the boot menu without doing the ritual with the troubleshooting menu.

Test mode doesn't eliminate the signature checks, but allows users to sign drivers themselves. This can be permanently enabled, but shows a warning text in the lower right corner of the desktop and also requires the extra step of manually signing the driver in order for it to work.

Doesn't DSEO work with Windows 8? I guess not since it's not listed in the compatible OSs. Otherwise, can't you press F8 when booting, like you can with Windows 7?
If Windows 8 is anything like Windows 7, you could try opening an administrator command prompt and doing the following command. This should make the Windows boot manager show up for 1 second on each boot, which should allow you to press F8, again, unless Windows 8 is different in this regard.

bcdedit /set {bootmgr} timeout 1

Nope; Windows 8 doesn't have the F8 boot menu thing.
Also, DSEO doesn't work with Windows 8. Can't even use it to go into Test Mode.
I just used the "special restart" thing and disabled driver signature enforcement.

bcdedit /set {bootmgr} timeout 1

running it on a samsung tablet/laptop