Here is the long thread of how I got this to work here:
www.raspberrypi.org/forums/
Summary answer of the thread(it should be noted that the only way I got this to work on a Windows PC was by having a virtual machine running Ubuntu 14.04 so I could copy and edit files):
A 2018-03-13-raspbian-stretch.img file to a USB stick(I did this via Win32DskImager.)
A ubuntu-mate-16.04.2-desktop-armhf-raspberry-pi.img to a USB stick(I did this via Win32DskImager.)
Using a Ubuntu 14.04 virtual machine mount both USB drives. You should see four disks: PI_BOOT, PI_ROOT, boot and rootfs.
Run the following commands for copying files(you will need to change the "john" portion of the path to match the location on your virtual machine):
sudo cp -r /media/john/rootfs/lib/modules/4.9.80+ /media/john/PI_ROOT/lib/modules/
sudo cp -r /media/john/rootfs/lib/modules/4.9.80-v7+ /media/john/PI_ROOT/lib/modules/
sudo cp /media/john/rootfs/lib/firmware/brcm/brcmfmac43455-sdio.txt /media/john/PI_ROOT/lib/firmware/brcm
sudo cp /media/john/rootfs/lib/firmware/brcm/brcmfmac43455-sdio.clm_blob /media/john/PI_ROOT/lib/firmware/brcm
sudo cp /media/john/rootfs/lib/firmware/brcm/brcmfmac43455-sdio.bin /media/john/PI_ROOT/lib/firmware/brcm
sudo cp /media/john/boot/bootcode.bin /media/john/PI_BOOT
sudo cp /media/john/boot/fixup.dat /media/john/PI_BOOT
sudo cp /media/john/boot/start.elf /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2710-rpi-3-b-plus.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/kernel.img /media/john/PI_BOOT
sudo cp /media/john/boot/kernel7.img /media/john/PI_BOOT
I'm not positive that these files are necessary...
sudo cp /media/john/boot/bcm2708-rpi-0-w.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2708-rpi-b.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2708-rpi-b-plus.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2708-rpi-cm.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2709-rpi-2-b.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2710-rpi-3-b.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2710-rpi-3-b-plus.dtb /media/john/PI_BOOT
sudo cp /media/john/boot/bcm2710-rpi-cm3.dtb /media/john/PI_BOOT
To edit the next files you need to be super user so launch gedit from the command line with
sudo gedit
From gedit change the /media/john/PI_BOOT/cmdline.txt
file so that root=/dev/sda2
From gedit change the /media/john/PI_ROOT/etc/fstab
file to:
proc /proc proc defaults 0 0
/dev/sda2 / ext4 defaults,noatime 0 1
/dev/sda1 /boot vfat defaults 0 2
Unmount the drives from the virtual machine and place the Ubuntu Mate USB in the Pi 3 and boot.