Nerves: I can't upload firmware for `subsystem request failed` error

After upgrading nerves_bootstrap 1.9.0, I can’t upload firmware to target any more for the error.

  1. mix app --> make a new project
  2. mix deps.get --> The comments came out.
A new version of Nerves bootstrap is available(1.8.1 < 1.9.0), You can update by running

  mix local.nerves
  1. after update the above, mix deps.get runs.
** (RuntimeError) :nerves_ssh isn't configured, but :nerves_firmware_ssh is.

This is probably not right. If you recently upgraded to :nerves_ssh or
a library that uses it like :nerves_pack, you'll need to edit your config.exs
and rename references to :nerves_firmware_ssh to :nerves_ssh.
  1. modified nerves_firmware.ssh to nerves_ssh as the comments in config/target.exe

  2. mix firmware and ./upload_sh execute

 $ ./ 
Path: ./_build/rpi3_dev/nerves/images/connect.fw
Product: connect 0.1.0
UUID: f524800a-2aa7-5f60-7bec-f3a86f32caa3
Platform: rpi3

Uploading to nerves.local...
subsystem request failed on channel 0

After all I can’t upload because of subsystem request failed

I check the previous project if I can upload or not with compiling processes. This case is all right.
.ssh/ is the same.
And ssh nerves.local passes to make a remote terminal.
I upgrade fwup 1.8.0 -> 1.8.1 but this didn’t solve the issue.

I assume that ssh_subsystem_fwup which is deps of nerves_ssh has something wrong and I should set something on configuration.

Could you please tell me how to solve this?


Thanks for posting so many details. I’ll try to explain what’s happening and what you can do to fix it.

The switch from nerves_firmware_ssh to nerves_ssh changes the TCP port number that firmware updates get sent. nerves_firmware_ssh uses TCP port 8989. nerves_ssh uses TCP port 22. Why the change of ports? The short story is that it centralizes SSH daemon configuration - IEx prompt, SFTP, and firmware updates all get authenticated the same way.

It looks like you are using the script from nerves_ssh to update a device that is running nerves_firmware_ssh. The "subsystem request failed" error is due to the upload script trying to send the firmware file to an ssh subsystem on TCP port 22. That doesn’t exist with nerves_firmware_ssh so you get an error.

To fix this:

  1. Find a nerves_firmware_ssh script or download this one. Call it
  2. Run ./ to push the new firmware to the device
  3. Subsequent uploads should be done with the new script (since nerves_ssh is now running on the device).

Another option is to continue to use nerves_firmware_ssh. If you’re using nerves_pack to pull in firmware update support, lock your nerves_pack dependency to ~> 0.3.0.

I hope this fixes your issue.


Thanks a lot for your leading.

The trouble of upload has been solved by following your comments.

And I am so sorry to miss reading document although I intended to read it. I should have checked it more carefully.

I appreciate your kind response and help again.

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