To support the writing of image updates to the simple board computer (SBC), you need to think carefully about your Raspberry Pi and the SD card in it. A key consideration is writing to the SD card and not wearing out the flash memory. If the flash memory does get worn out before the end of the lifecycle of your device, the device will stop working. Then the device will have to be manually replaced by a technician in the field. So it is key to be aware of excessive usage as flash memory has a limited number of times it can be written to.
This is a companion discussion topic for the original entry at https://mender.io/blog/memory-requirements-for-your-raspberry-pi