I have a Raspberry Pi 4 where the firmware has been updated to allow booting from a USB drive. I’ve successfully booted a minimal Ubuntu from a USB thumb drive on it.
For NixOS though I think there needs to be some extra steps beyond making a UDB drive image of the Aarch64 ISO? The Pi doesn’t have a conventional UEFI/uboot setup? Perhaps I need to go via an SD card, then install NixOS on an empty USB drive?
If anyone has successfully done this I’d love ot hear about your approach.