> You can do that but you'll need a way to generate the checksum for the seed phrase. A 24 words BIP39 seed contains 264 bits (24 x 11 bits): 256 bits for the seed and 8 bits for the checksum.

In theory, you could pick 23 words at random with 11 * 23 coin flips, every 11 flips representing an index in the dictionary. Now to find which 24th word passes the checksum, you could guess it in at most 2048 attempts on your hardware wallet :)

More realistically, it might be possible to develop a Ledger app that, given 23 words, finds the "checksum-passing" 24th word for you.