For the WRT1200AC the docs - also the old openWRT docs describe that it should be flashed using an USB-TTL cable and run update_both_images
Then, boot_part 1 and 2 are flashed.
If you start up to stock firmware and flash via Luci, it seems like the boot_part 2 gets flashed only. In that case, if smth happens, the system starts up in failsafe (?) mode which leads to a start up of (stock) firmware on boot_part 1.
Can anyone confirm that behaviour?
I was running LEDE (lede-17.01.4) on boot_part 2 only and it was very unstable. It was periodically (2-3 times per hour) restarting for some reason and ended up in stock firmware on boot_part 1 (as it seemed). Reboot with power cable unplug helped.
Now, I am running LEDE in boot part 1 and it seems like this is always booting, also in case of failsafe mode. Can anyone confirm that?
It also seems to be much much faster (50 mbit instead of 10) than before.
Do other models also have two boot parts that can be flashed?