How to fix wifi for an unsupported Realtek 8852 adapter in the current GMKTec NucBox G3 running Linux Debian based OS

I just bought a CUTE and TINY, dirt cheap and brand new (NOT refurbished!) GMKTec NucBox G3 mini-PC to replace Momsy's PC that just died, and set it up with Linux Mint Debian (LMDE). There was just one thing...

UPDATE on 2025-10-05: 
You can probably skip a ton of stuff. I just installed the latest Linux Kernel image in another NucBox, complete with headers. No extra drivers needed! 
Installing 6.12.43 was all I had to do, when trying out a few other "distros" (distributions) in the last few weeks! The newer Linux versions just digested every device in my new "NucBox 3G Plus". 
This is because telling hardware what to go do with itself is in the kernel.  

So Momsy's PC died, and gone was her solitaire, Mahjong, and daily news, and email with Germany!

Maybe I could have fixed the old refurb box, but after a day of head scratching, and looking at what we had, it was time to move on to a better machine. After a lifetime of tinkering on tight budgets building and fixing Franken-puters, I am tired of messing around. We splurged for a bit over 100 bucks!

The NucBox G3 is now a sweet machine, dead quiet, even with the CPU running, very snappy, and boots fast, in under 30 seconds, compared to the over 2 minutes for the old spinning disk tech Acer model. 

It is altogether amazing, but had ONE problem: 

The built in wifi module was not working with Linux Mint Debian, and according to web comments, on no Linux version at all.

I HATE Windows with a passion, mainly due to the incessant huge updates, that eat my meagre cell-phone tethering/hotspot only connection for up to a couple of days! Mind you, it works dandy for streaming Netflix and Amazon Prime Video, and I BINGE all day. Being at home disabled with a bummer heart defect and stroke after effects, it is better than just dozing! 

Aside from the steady Gigabyte sized updates, there are also tons of privacy problems, bugs, and stuff that Microsoft never admits to, as I know from working in a tech centre for many years. 

So, OUT with Winedoze (I saved that solid state drive in case insanity makes me buy a game, and plugged in a blank SSD for 20 bucks, no biggy), and here comes Linux! Everything worked after plugging in the live/installer image USB-stick with Mint Debian, aka LMDE, except wifi, same with straight Debian. Momsy is used to Mint, it has far better wall-papers, and I wanted Momsy to notice no difference, so Mint it was!

I could have just plugged a spare external wifi dongle, as the old machine did not even have internal wifi, but I was curious. The solution finally came after about 3 searches happened to hit the right keywords and lead me to a good solution!

WARNING: 

If the stuff below makes no sense, YOU ARE NEW TO LINUX, SO JUST USE AN OLDER EXTERNAL WIFI ADAPTER!

A new installation of current Linux Mint (YEAH!), Debian (YEAH!), or Ubuntu (which I like as much as Windoze... NOT) will pick up an older (2 years?) wifi adapter without problems. You may need an extra USB splitter, but it is the easy solution. 

Here is what you need, and don't ask me to tutor you, lest you are willing to pay me a tutoring fee!

AT YOUR OWN RISK

This worked for me:

THE REALTEK 8852 NEEDS THE LATEST KERNEL, and was not recognised with my 6.1 series kernel! 
This means, you need to use your "Software Manager" or "Synaptic Package Manager" to search for the latest kernel, that is preferably signed AND matches the CPU type of the other already installed and known functional kernels. Currently (as of 9 Sept 2025), this is version 6.12 for Linux Mint Debian, but a few months earlier I had read, that 6.5 would work as the then latest.

+++++++++++++++++++++++++++++
sudo apt update && sudo apt install linux-image-generic
(this may or may not get a kernel that works, as mentioned above, a manual search with package and software managers may be required)
+++++++++++++++++++++++++++++

NEXT, install the drivers:

To install the Realtek 8852 driver on Mint Debian, you'll need to download the "rtw89" driver from GitHub, compile it manually, and then install it using the following steps:
 
1. Update system and install build tools:
Open a terminal and run.
+++++++++++++++++++++++++++++

sudo apt update

sudo apt install build-essential git linux-headers-generic


2. Download the rtw89 driver:
Clone the repository from GitHub.
+++++++++++++++++++++++++++++

git clone https://github.com/lwfinger/rtw89.git

cd rtw89


3. Compile the driver:
• Run the following command to compile the driver for your kernel:
+++++++++++++++++++++++++++++

make


4. Install the driver:
Install the compiled module.
+++++++++++++++++++++++++++++
sudo make install

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