I've got two boards with the exact same issue, and it's confusing the hell out of me. In short:
1. Both boards behave *exactly* the same; they will show WiFi networks to connect to, and will boot fully to Internet Recovery, but they each show zero available WiFi networks once booted to Internet Recovery. I also cannot switch WiFi "off", as in, the toggle will not move.
2. Both boards will erase perfectly fine using the "erase mac" function; I can wipe them with disk utility, but if I try to install MacOS from Internet Recovery, it says to connect...
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