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new 4a927bc7e00 Documentation/applications: document Dropbear scp file
transfers
4a927bc7e00 is described below
commit 4a927bc7e00d441a7ace46d63135d27973c0cb14
Author: Felipe Moura <[email protected]>
AuthorDate: Sun Jul 5 13:31:26 2026 -0300
Documentation/applications: document Dropbear scp file transfers
Document how to transfer files with scp on the Dropbear server port,
which requires the legacy protocol (scp -O) since the port has no SFTP
server. Recent OpenSSH clients default to SFTP and fail otherwise.
Signed-off-by: Felipe Moura <[email protected]>
---
.../applications/netutils/dropbear/index.rst | 36 ++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/Documentation/applications/netutils/dropbear/index.rst
b/Documentation/applications/netutils/dropbear/index.rst
index d0c86ac8776..aed5394ec84 100644
--- a/Documentation/applications/netutils/dropbear/index.rst
+++ b/Documentation/applications/netutils/dropbear/index.rst
@@ -77,6 +77,35 @@ Then open an SSH session from a host on the same network::
<username>@<ip_address>'s password:
nsh>
+File transfer with scp
+----------------------
+
+When ``CONFIG_NETUTILS_DROPBEAR_SCP`` is enabled (default ``y``, requires
+``CONFIG_PIPES=y``), Dropbear's ``scp`` program is built as a builtin
+application and the server accepts SSH ``exec`` requests, allowing files to
+be copied to and from the board with a standard ``scp`` client.
+
+The port implements only the legacy scp protocol. OpenSSH 9.0 and later
+default to the SFTP protocol, which is not supported by this port, so a
+plain ``scp`` invocation from a recent Linux distribution fails. Pass the
+``-O`` flag to force the legacy scp protocol.
+
+Copy a file from the host to the board::
+
+ $ scp -O <file> <username>@<ip_address>:/data/<file>
+
+Copy a file from the board back to the host::
+
+ $ scp -O <username>@<ip_address>:/data/<file> .
+
+When Dropbear listens on a non-default port, add ``-P <port>``::
+
+ $ scp -O -P 2222 <file> <username>@<ip_address>:/data/<file>
+
+Transfers must always be initiated from the host. Running ``scp`` on the
+target to push or pull files from another machine is not supported, since
+the port does not include an SSH client.
+
Notes
-----
@@ -120,6 +149,13 @@ Remove the stale entry with::
Then reconnect normally. The client will prompt to accept the new host key.
+**scp fails with "subsystem request failed" or "Connection closed"**
+
+Recent OpenSSH clients use the SFTP protocol by default, which this port
+does not support. Retry forcing the legacy scp protocol::
+
+ $ scp -O <file> <username>@<ip_address>:/data/<file>
+
**Connection refused**
Check that the board has obtained an IP address and that the Dropbear task is
