Поломали dropbear на последнем обновлении, так же как и busybox:
opkg install dropbear
Installing dropbear (2025.89-1) to root...
Configuring dropbear.
Generating 2048 bit rsa key, this may take a while...
Public key portion is:
ssh-rsa .....
root@localhost
Fingerprint: ...
Unknown key type 'ecdsa'
Usage: /opt/bin/dropbearkey -t <type> -f <filename> [-s bits]
-t type Type of key to generate. One of:
rsa
ed25519
-f filename Use filename for the secret key.
~/.ssh/id_dropbear is recommended for client keys.
-s bits Key size in bits, should be a multiple of 8 (optional)
Ed25519 has a fixed size of 256 bits
-y Just print the publickey and fingerprint for the
private key in <filename>.
-C Specify the key comment (email).
Generating 256 bit ed25519 key, this may take a while...
После этого dropbear запускается, но не принимает ключи. Откат на старую версию 2024.86-1 решает проблему.