OpenWRT newb here. I ordered a One router. It booted out of the box with the stock image. I changed the device name and password. When it rebooted it stopped responding. I can no longer log in with openwrt.lan or 192.168.1.1 or get a response. I pushed the reset for 10 seconds. I reboots within 20 seconds, it does not take 2 minutes as if it were re-imaging.
When I restart, the white light flashes for a bit then green lights.
Disclaimer: I have no personal experience with the OO, but…
Given the rather unique hardware features of the OO, you have very easy access to the serial console (the USB-C port marked as console). Just connect a computer with a USB cable to this console port, start your preferred terminal emulator for this interface and you can see what the OO is doing (and fix it in place, and be it by invoking firstboot). Having serial console access this easily available is rarely found on routers, but it can make debugging/ recovering really easy, as you don't need to act blindly and can actively interact with the router at all stages.
All of the 'normal' recovery methods (as well as NOR booting, flashback, mtkuart, etc.) also remain available, of course.
Select the SYSUPGRADE image, to download the image to your PC.
In LuCI select System > Backup/Flash Firmware Select FLASH IMAGE and follow the prompts to download the image to the router and flash the upgraded NAND image.