The RevolutionPi Flat module has no USB eMMC Interface. Is it still possible to upload an image?
For the flat, there is ultimately only the possibility to set up over-the-air updates and thus exchange images. The prerequisite is that an executable image is on it beforehand. http://mender.io is such a tool or Ansible could also be used for this. Since our image is based on Debian or raspios, you have all the other possibilities of the Linux world at his disposal. Cloudrail uses uboot, have changed the partitioning and written a few shell scripts to update their image/kernel at runtime and over the net.