I made the sad retarded mistake in updating a manual zip file thru CMW... I know retarded... anyways this caused the tablet to Hard Brick bootloader only with very little options, you might even have your serial number showing up as all 1's.
Usually this isn't a big deal sadly this tablet gets little to no love on the internet it seems... This is a guide to help anyone un-brick their tablet
Step 1. First this is more of a windows 10 issue than anything but some driver installs thru the Asus Flash Tool might fail.. something to do about Driver Certificates, so you'll want to disable that on your Win 10.. here a tutorial link for more youtube link HERE
Step 2. Installing the proper Drivers if you haven't already, which will all be in this zip folder HERE
Make sure you installed the ADB-Setup | Intel Android Drv Setup | Asus Android USB Drivers | Asus Flash Tool Installer 1.14
Step 3. Next you'll want to download the .raw file for the ZenPad can be found HERE
Step 4. Open your Asus Flash Tool Installer, boot up your device in the boot mode. (Hold Down the Volume Up + Power ) till you see a little android man with a hardhat.
Step 5. Plug in your device and you should see your device show up as shown HERE, next you'll want to select the model in the model drop down.... Z580C or Z580CA.. then select file. Now if it only lets you select zip thats okay. On the open file dialog box you'll see you can type in the file, simply type in the file path of the .raw file. Once you have that check on Erase Content which will erase all your internal content, and hit flash... let it run until the blue light on the program is green and has flashed succefully.
Now you may still get on a bootloop when it restarts, if that happens simply again restart in boot loader screen and do a hard reset and you'll be good to go! Afterwards just throw that new Marshmallow update in the internal and restart .. and you'll device will ask if you want to update now u got your tablet back and Marshmallow!!! I hope this helps if you have any troubles with the links, images please feel free to let me know pm or reply to this post!!! Best of Luck!
.RAW File was provided by Portzebie! Thanks again bud!!