Noob question: I want to change host key on my Remarkable 2 tablet about dropbear HOT 2 CLOSED

The problem is that Dropbear version has a bug where it'll offer RSA even if there's no key available, and then crash. (The bug's fixed in a newer version).

The first thing to try might be to add --sftp-host-key-algorithms ed25519 to rclone, that won't have any risk on the device itself. https://rclone.org/sftp/#sftp-host-key-algorithms

Otherwise, I think you should be able to just add one extra ExecStart line on the Remarkable to create the rsa key in the default location, and Dropbear will then use that. Keep the existing Execstart ...dropbearkey -t ed25519 line, and after it add

ExecStart=/usr/sbin/dropbearkey -t rsa -f ${DROPBEAR_ED25519KEY_DIR}/dropbear_rsa_host_key

You could run that from a commandline to try.

Keep a couple of backup SSH windows open if you're editing things, then there's better chance for recovery if something goes wrong.

from dropbear.

Thank you @mkj !

Adding --sftp-host-key-algorithms ssh-ed25519 to my rclone commands worked. I don't need to change anything on the tablet. What a relief! 😁

from dropbear.