Have you tried remeshing? it is in my opinion much more stable.
There are also implementations for accessing the console over ssh.
here is one example of setting it up

Even later reply. If you setup nerves_firmware_ssh, you should be then able to SSH (by default on port 8989) directly into the Erlang console. From there, just type 'Elixir.IEx':start(). to start an IEx console.

In fact, nerves_firmware_ssh makes use of the Erlang SSH module mentioned in the link posted above.

Hope this helps

I am using a separate SSH daemon, which runs the IEx shell:

system_dir = Nerves.Firmware.SSH.Application.system_dir()
{:ok, _ref} = :ssh.daemon(22, password: 'password', system_dir: system_dir, shell: {IEx, :start, []})

It’s not particulary secure in that way, but gets the job done.