[Cootey]

TL;DR I’m afraid those steps don’t work anymore. They are nine years out of date.

Details below:

Spoiler:

The first problem is that most of the processes that are listed in those directions don’t exist anymore. The second problem is that, although the principle is to kill any process that accesses /mnt/onboard, there is only one process listed by ps in the modern firmware that does so: tcpsvd. Killing that process is easy. The problem is that something else is accessing that directory that refuses to let me unmount /mnt/onboard.

I ran “lsof +r2 | grep ‘/mnt/onboard’” to see which process was the culprit. It wasn’t good news.

Nickel is what has got its hooks into that directory. You can kill it, but after a few moments, the Kobo reboots. As expected.

I can successfully get netcat running a tunnel to the Kobo, but I can’t finish typing the command to start the backup in another terminal before the Kobo reboots.

As far as I understand, Nickel is the OS. I don’t think it’s possible to suspend nickel without causing the Kobo to crash.

Maybe somebody who knows more about Linux than I do can pipe up and give us their input, but it seems that the answer to the OP’s question is “no”.