On Sun, Jan 31, 2021 at 11:47:04AM +0100, Stefan Sperling wrote: > In general, crypto softraid volumes don't auto-assemble.
I forgot that softraid volumes that use a key disk instead of a passphrase will auto-assemble. Have you already tried that? A disklabel slice on the USB key could act as a key disk for the encrypted volume on the internal disk.