PrusaLink on Raspberry Pi (MK3S+) No LAN Access fix  

PrusaLink on Raspberry Pi (MK3S+) No LAN Access fix

Hey! 

Almost pulled my hair out trying to get my Pi 4B connected to the WiFi when using PrusaLink 0.8.1, so i thought i'd make a quick post detailing what i did to fix it.
This probably won't work for people using a Pi Zero in a MK3(S/+) because you don't have an ethernet port, but maybe there is a way around that with a USB dongle or something? Not too sure.

Be aware: i'm not a networking savvy person. I got through this by trying a million different dumb ideas and seeing what stuck. If you're knowledgable about SSH, Linux and networking in general, this will probably seem trivial. I'm simply putting this out there for other clueless people like myself who are searching Google for answers.

Backstory: I probably flashed the SD card around 15 times with the same message appearing on my printer every time: No LAN Access.
It didn't show up on my routers dashboard thingy either, so i figured the WiFi SSID must be broken or something. I tried putting the wpa_supplicant file in the boot partition before inserting the card into the Pi for the first time, but that also did nothing. I got lost in a rabbithole of how country codes work (spoilers, not that important as long as it's somewhere near you, or so i'm told).
So, here was my final attempt that (thankfully) finally worked.

----------------------------------------------------------------------------

First of all, while flashing the SD card again i enable SSH in the options tab of the Pi imager custom OS settings page. I also set a username and password (just above SSID). Click save, click "yes" to using custom os settings when writing, then wait for it to finish as usual. I then plugged the Pi into power, hooked up an ethernet cable to it and i then looked up a YouTube tutorial for how to SSH into a Raspberry Pi.
Once i had access to the Pi through Powershell, i typed the following into the console: sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

That opens up a funny looking text editor thing, where i edited it until it had this information (replace dummy data with actual values of your WiFi credentials and country code - DK is Denmark, find out what yours is)

country=DK
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
    ssid="YOUR_SSID"
    psk="YOUR_PASSWORD"
    key_mgmt=WPA-PSK
}

Once that's all done, press CTRL + O to save, then Enter to confirm writing it, and finally CTRL + X to exit the thingy.
Next, put the following into the console: sudo wpa_cli reconfigure
This should restart the network part of the Pi, but mine just said failed. No clue what that's about.
Anyway, to check if it actually worked, i typed the following into the console: iw wlan0 link
That should hopefully return an IP address on wlan and the SSID you just put into the wpa_supplicant file. 

Once i got confirmation that it was now connected, i unplugged the Pi from power and ethernet, took it to my printer, plugged it in and waited - and it worked.

If any smart people happen to check this thread, please do correct any misinformation or improvements to the process.
And if you're trying this fix, and it doesn't work, feel free to ask (can't promise i can help but i'll try).