10+ R Pi's, linux image, remote maintenance, offline mode

I've been asked to create 10+ ticket scanners with printers. I'm planning on using Raspberry Pi 3 for each terminal, connecting the scanner, printer and touchscreen. My concern is about maintenance...

In an ideal world, I'd like to
- connect the Pi to the web and use PXE to automatically download and install the latest image on the SD-card on first boot. Could also just manually flash every card, but the former is ideal
- be able to update every Pi remotely, preferable just send an entire new image

I don't think I can use PXE to always run the latest image upon reboot, since the terminal needs to work offline, in which case it might shutdown before getting to send registered participants to the web.

Are there any ways to do this? Are there better ways to maintain that many terminals?

Okay, I might be able to use PXE. Don't know why I didn't think about it, but running the OS completely in ram and using the sd card for storage if the terminal goes offline is of course the way to go. If you have better/other ideas please do post them

Not really. Here is the tutorial for network booting a Pi.

https://www.raspberrypi.org/document...et_tutorial.md

I remember using a Psion2 about 20 years ago which used a barcode scanner, printer and modem to do basic POS functions. Programs were burnt onto 256KB EEPROM's.