T2 Mac with empty internal storage won't boot from install USB Every year or so I like to do a fresh install of Mac OS on my machines. The method I've always used is to download the OS from the App Store, create an installable USB with Terminal, boot into the USB, format the internal storage and then install.
This has not worked on my most recent Mac, which is a 2018 Intel Mac mini (the only one I have with a T2 chip). It first wouldn't let me boot into the USB due to a security restriction, so I rebooted into recovery mode and formatted the internal storage there. Before restarting I attempted to restart to the USB with Target Disk Mode, but it wouldn't pick up my USB within about a minute of waiting (maybe I should've waited longer) so I just restarted it normally and tried once again to boot to the USB on startup.
Every time I select the USB device on startup, it falls back to internet recovery mode. The yellow USB drive icon just instantly turns into the globe and prompts me to connect to WiFi. I've tried this method a few times but it sounds like any blip in the connection causes it to give up, and this has happened to me 4 times now. Is there any reason why a T2 Mac with no OS would not boot to a USB device? Is there anything else I can do besides retry internet recovery until it finally downloads everything in one go?
Thanks!
UPDATE: I did eventually get Internet Recovery working. See my answer below
I did eventually get Internet Recovery working. I was getting various errors (-1008F, -2106F and perhaps others) after long periods of time spent waiting for the boot to complete. While some of these may have been down to a shoddy internet connection, it seemed as if it would just error immediately after the bar had reached 100%.
After doing a bit of digging I removed the Mac from my iCloud account via appleid.apple.com as well as perform all steps on this guide to restore a Mac with Apple Configurator 2 (I found about that on this thread). You will need an additional Mac on hand to do the latter.
After doing that, then booting with Internet Recovery and then reinstalling from the recovery menu I still needed to log in using my iCloud credentials as well as my old local account. Fortunately for me that wasn't a problem at all, but bare that in mind if anyone reading is in a similar situation!