After an agonizing weekend of trying to get Windows 10 working with Wi-Fi, I decided to create an image of the eMMC so I wouldn't have to go through that again.
On other computers, I'd just boot into a live Xubuntu environment, connect to the Internet via Wi-Fi, install exFAT utilities from apt, and then use dd to image the drive and write to an exFAT drive.
But because of the limited port selection and lack of power delivered to the ports, it's a different story for this special snowflake.
The contents of this guide will talk specifically about how I managed to backup and restore the contents of the eMMC.
Your mileage may vary.
Also, this was written up on 4 AM on a Monday, so it's not gonna be the best guide. Not yet at least. A more thorough guide and better explained guide will follow... hopefully.
Connect the USB OTG cable to the microUSB port. Since this probably provides less power, let's just connect our wirleess keyboard and mouse to this port.
Connect the 4-port USB hub.
Connect the Ubuntu flash drive, exFAT flash drive, and Android phone to the 4-port USB hub.
Boot into the BIOS by (repeatedly) hitting Esc while turning on the tablet.
Boot into Ubuntu by selecting the flash drive it is installed on in the Boot Manager.
Enable USB tethering on your Android phone so our Ubuntu environment can connect to the Internet. Ubuntu will not recognize the on-board network card.
Run sudo add-apt-repository universe and sudo apt-get install exfat-fuse exfat-utils so Ubuntu can recognize our exFAT flash drive.
In case the drive doesn't show up on the Desktop, we can manually mount it by running lsblk to check its path, and then sudo mount -t exfat /dev/sdXY /media/ubuntu/exfat to mount the drive. Make sure /media/ubuntu/exfat exists!
Take note of the name of the eMMC with lsblk. It will most likely be mmcblk0.
Run sudo dd if=/dev/mmblk0 of=/media/ubuntu/exfat/cubix.img bs=64k conv=sync,noerror status=progress and it will (slowly) start imaging the drive.
Connect the USB OTG cable to the microUSB port. Since this probably provides less power, let's just connect our wirleess keyboard and mouse to this port.
Connect the 4-port USB hub.
Connect the Ubuntu flash drive, exFAT flash drive, and Android phone to the 4-port USB hub.
Boot into the BIOS by (repeatedly) hitting Esc while turning on the tablet.
Boot into Ubuntu by selecting the flash drive it is installed on in the Boot Manager.
Enable USB tethering on your Android phone so our Ubuntu environment can connect to the Internet. Ubuntu will not recognize the on-board network card.
Run sudo add-apt-repository universe and sudo apt-get install exfat-fuse exfat-utils so Ubuntu can recognize our exFAT flash drive.
In case the drive doesn't show up on the Desktop, we can manually mount it by running lsblk to check its path, and then sudo mount -t exfat /dev/sdXY /media/ubuntu/exfat to mount the drive. Make sure /media/ubuntu/exfat exists!
Take note of the name of the eMMC with lsblk. It will most likely be mmcblk0.
Run sudo dd if=/media/ubuntu/exfat/cubix.img of=/dev/mmblk0 bs=64k conv=sync,noerror status=progress and it will (slowly) start writing the contents of the image to the drive.