This article covers creating a bootable USB drive to operate the Douro from, in lieu of its internal SSD drive entirely. It can be used as a full replacement drive, with no performance impact.
This as opposed to reimaging the Douro's internal drive, which is another possibility.
Identify your tablet model
NOTE: This article is only relevant to Douro's with ACP-1103 model tablets (shipped between 2014 and December 2016). If you have an ACP-1104 tablet, you must use the article Reimaging the Douro in order to reset it to the default image.
You can determine which model your tablet is by whether the USB port next to its power button is USB 2.0 (black) or 3.0 (blue). The ACP-1104 has one USB 3.0 port, the ACP-1103's are all USB 2.0.
Download the image
Download the Lamassu drive image (around 3 GB):
The lamassu-machine version contained in the image is v7.1.1
Flashing the drive
You'll need a 32GB USB 3.0 drive with a compact profile. We recommend this Samsung drive.
Disconnect all external drives and devices connected to your computer, except for the destination USB drive.
Download and install Etcher (available for Linux, Mac, and Windows): https://etcher.io/
In Etcher, select the image file downloaded earlier, then select the destination USB drive and click flash.
WARNING: Be very careful when selecting the destination drive, ensuring that you correctly point it to the destination USB drive and not that of any other devices you have connected, as the command will result in full data loss to the destination.
Booting from the drive
Once complete, eject the USB drive from your computer and follow this article in order to boot the Douro from it: Booting from a Lamassu image drive (ACP-1103)