[Help] SCP fails unless using legacy mode (-O) - SFTP subsystem appears broken

[nenominal]

Hi,

I have an F2-425 Plus running the latest TOS 6.x branch (6.0.794-01324) and I want to use scp to transfer files.

I'm trying to use scp to transfer files to/from my NAS, but it fails with "connection closed."
However, if I use scp -O (legacy mode), the transfer works fine. I've attached a screenshot showing both attempts.

I looked into it and the issue seems to be with the SFTP subsystem. In sshd_config, the subsystem is configured to point to /usr/lib/openssh/sftp-server, but that file doesn't exist on the system.

The openssh-sftp-server package only installs /usr/sbin/sftpd, and when I run it with --help, it actually shows sshd usage — so it looks like it's not the right binary.

Is this a known issue, or is there something I need to configure differently to get normal SCP (non-legacy) and SFTP working?

[TMnight]

Thank you for your feedback.
We have confirmed that this issue does exist and is related to compatibility. We recommend using scp -O as a temporary workaround for file transfers.

This issue has been reported to our product team and will be evaluated for optimization in a future update. We appreciate your patience and understanding.