OK - I have successfully followed the instructions listed here:
Kudos to very clear instructions that a complete xiaomi newbie like me could follow w/out bricking the device.
I now have root access to it, but it is still creating its own private WLAN. Is it now time to connect to it with the iOS app again and configure it for the local network?
I'm being cautious since I don't want it updating itself and undoing all my work thus far.