# Nimmo's NixOS Setup Guide (Host: electra)

## 0. Pre-Installation Preparation (Do this NOW on CachyOS)

Since you are hosting this on `git.nimmog.uk`, we will create the config locally and push it before booting the installer.

1. **Create the Repository on your Server:**

   * Log into `https://git.nimmog.uk`.

   * Create a new **empty** repository named `nixos-config`.

   * *Do not initialize with README or license (keep it empty).*

2. **Create Files Locally:**
   Open a terminal in CachyOS:

   ```
   mkdir ~/nixos-config
   cd ~/nixos-config
   
   # Run the creation script provided by Gemini to generate files here
   ```

3. **Initialize & Push:**

   ```
   git init
   git branch -M main
   git add .
   git commit -m "Initial commit: Setup for electra"
   
   # Replace with your actual SSH or HTTPS URL
   git remote add origin https://git.nimmog.uk/YOUR_USERNAME/nixos-config.git
   git push -u origin main
   ```

## 1. Initial BIOS Setup (Crucial)

Before booting NixOS, you must configure the BIOS to handle the memory split for your LLMs.

1. Reboot and enter BIOS (usually F2 or Del).

2. Find **Graphics Memory**, **UMA Frame Buffer**, or **iGPU Memory**.

3. Set this to **16G** (or "Game Optimized" if it equates to high memory).

## 2. Installation

Once you have booted the **NixOS Unstable ISO**, choose your path below.

### Path A: Fresh Install (Wipe Everything)

*Use this if you want to start completely fresh.*

1. **Partition:** `cfdisk /dev/nvme0n1` (Delete all, Create 4G Boot + Remaining Root).

2. **Format:**

   ```
   mkfs.fat -F 32 -n BOOT /dev/nvme0n1p1
   mkfs.btrfs -L nixos /dev/nvme0n1p2
   ```

3. **Create Subvolumes:**

   ```
   mount /dev/nvme0n1p2 /mnt
   btrfs subvolume create /mnt/@
   btrfs subvolume create /mnt/@home
   btrfs subvolume create /mnt/@nix
   umount /mnt
   ```

4. **Proceed to Step "Mounting" below.**

### Path B: Migration (Keep /home data)

*Use this to delete CachyOS but KEEP your existing data in `@home`.*

1. **Mount the Top-Level Partition:**

   ```
   mount /dev/nvme0n1p2 /mnt
   ```

2. **List & Cleanup:**
   Run `ls -a /mnt`.
   **Delete the OLD Operating System:**
   *Warning: Be extremely careful. Do NOT delete `@home`.*

   ```
   # Delete the old root and system folders
   btrfs subvolume delete /mnt/@
   btrfs subvolume delete /mnt/@root
   btrfs subvolume delete /mnt/@srv
   btrfs subvolume delete /mnt/@log
   btrfs subvolume delete /mnt/@cache
   btrfs subvolume delete /mnt/@tmp
   btrfs subvolume delete /mnt/@.snapshots
   ```

3. **Prepare NixOS Subvolumes:**

   ```
   btrfs subvolume create /mnt/@
   btrfs subvolume create /mnt/@nix
   ```

   *(Note: Ensure your existing home data is in a subvolume named `@home`.)*

4. **Format Boot Partition:**

   ```
   mkfs.fat -F 32 -n BOOT /dev/nvme0n1p1
   ```

5. **Unmount:**

   ```
   umount /mnt
   ```

### Mounting (Common for Both Paths)

1. **Mount Root (`@`):**

   ```
   mount -o compress=zstd,subvol=@ /dev/nvme0n1p2 /mnt
   ```

2. **Create Mount Points:**

   ```
   mkdir -p /mnt/{home,nix,boot}
   ```

3. **Mount Home (`@home`):**

   ```
   mount -o compress=zstd,subvol=@home /dev/nvme0n1p2 /mnt/home
   ```

4. **Mount Nix Store (`@nix`):**

   ```
   mount -o compress=zstd,noatime,subvol=@nix /dev/nvme0n1p2 /mnt/nix
   ```

5. **Mount Boot:**

   ```
   mount /dev/nvme0n1p1 /mnt/boot
   ```

### C. Deploy Configuration (Git Method)

1. **Clone Your Repo:**

   ```
   mkdir -p /mnt/etc/nixos
   # Replace USERNAME with your git.nimmog.uk user
   nix-shell -p git --run "git clone https://git.nimmog.uk/USERNAME/nixos-config.git /mnt/etc/nixos/"
   ```

2. **Generate Hardware Scan:**
   This creates `hardware-configuration.nix` in the folder.

   ```
   nixos-generate-config --root /mnt
   ```

   *(Ignore the warning about configuration.nix existing)*

### D. Install & Set Password

1. **Run the Installer:**

   ```
   nixos-install --flake /mnt/etc/nixos#electra
   ```

   *If prompted to set a ROOT password, go ahead and set one.*

2. **Set USER Password (Critical):**
   Do not reboot yet! We need to set the password for `nimmo`.

   Enter the new system environment:

   ```
   nixos-enter
   ```

   Set the password:

   ```
   passwd nimmo
   ```

   Exit the environment:

   ```
   exit
   ```

3. **Reboot:**

   ```
   reboot
   ```

## 3. Bus ID Configuration (Done)

* **NVIDIA:** 193 (`c1:00.0`)

* **AMD:** 194 (`c2:00.0`)

## 4. Applying Changes (Post-Install)

**To apply updates or config changes:**

1. Edit your files in `/etc/nixos/` (or pull changes from git).

2. (Optional) Commit your changes: `git commit -am "Update config"`

3. Rebuild:

   ```
   sudo nixos-rebuild switch --flake /etc/nixos/#electra
   ```

## 5. Boot Modes (Select at Boot)

You will see **four** options in your bootloader. Use arrow keys to select.

### 1. NixOS Default

* **Setup:** NVIDIA + Balanced Power (KDE).

* **Use when:** NVIDIA Module **INSERTED**.

### 2. Gaming-Zen

* **Setup:** NVIDIA + Zen Kernel + Max Performance.

* **Use when:** Gaming with NVIDIA Module **INSERTED**.

### 3. Eco-Battery

* **Setup:** NVIDIA + TLP (Max Saver).

* **Use when:** Traveling with NVIDIA Module **INSERTED**.

### 4. No-dGPU (Expansion Shell)

* **Setup:** **NO NVIDIA DRIVERS**. iGPU Only.

* **Use when:** You have physically **REMOVED** the GPU module and inserted the blank Expansion Shell.

* *Note: If you boot Default with the GPU removed, the system will likely fail to reach the desktop.*

## 6. Adding New Apps

* **CLI Tools:** Edit `system-utils.nix`.

* **GUI Apps:** Edit `user-apps.nix`.

* **After editing:** Run the rebuild command in step 4.

## 7. Docker

Docker is installed and running in Rootless mode. You can run docker commands immediately as user `nimmo`:

```
docker run hello-world
```

## 8. Fingerprint Reader

1. Go to **System Settings -> Users** and click "Configure Fingerprint".

2. If that fails, run `fprintd-enroll` in a terminal.

3. **Usage:**

   * **Login (SDDM):** Password only (required to unlock KWallet).

   * **Unlock Screen:** Fingerprint or Password.

   * **Sudo (Terminal):** Fingerprint or Password.