Adding a network to the Pi

I have a Raspberry Pi 3 here. It is setup to use my home network. Unfortunately I am not at home and I don’t have access to a tv that has hdmi. Normally I ssh in from my laptop but I can’t do that as I can’t see it on the network. I have the sd card in a reader and found my home network settings in preseed.cfg. Now that sounds like something that only runs when you first start the device. Is my assumption correct?

Now I could just copy off the config.txt, format it and copy back the config.txt. But I would have to reinstall a half dozen apps I have on there which will be a pain. With only my sdcard reader and a text editor can I add another network so I can use it whether I am here or at home and not have to worry (like I can with my phones, tablet, and laptop)?

I found one other topic that covers this via SSH (I need to get on the network first) and apparently “isn’t trivial” but doesn’t expand. The OP in that thread was going to mess around with the router which I have access to but rather I wouldn’t.

connman is our network manager. If you can find documentation to guide you in creating a network file then you might be able to connect to whatever network you are at. Good luck.

If you are connected via wired LAN, you can check your router config to see what your IP is.

Yes.

Edit preseed.cfg accordingly
Mount your SD card’s ext4 partition
Re-enable ftr.service

Unfortunately not, everything is wireless.

Doing a Google search for preseed.cfg gives me lots of hits for automated installs - not something I am doing.

Also your following steps of mounting the partition (I am guessing that you use a Linux box at home) and reenabling the ftr service doesn’t make much sense to me. I am afraid you will need to expand on those points.

Can you connect to a TV/monitor using the other video output - if so you should be able to get a usable display (possibly with mods to config.txt), and then you can input the other network details
Derek