# IOT-GATE-RPI4 Configuration - Debian Buster Migration

## Overview

The original `iotg-rpi4-config_1.3-1_all.deb` package was designed for Debian releases prior to Buster. Starting with Debian Buster, the boot partition structure changed:

- **Pre-Buster**: Boot files at `/boot/` (config.txt, overlays/)
- **Buster+**: Boot files at `/boot/firmware/` (config.txt, overlays/)

## Changes Made

The repackaged version `iotg-rpi4-config_1.3-1buster1_all.deb` includes:

### 1. Script Path Update
**File**: `usr/local/bin/iotg-rpi4-functions`
```bash
# Before
CONFIG=/boot/config.txt

# After
CONFIG=/boot/firmware/config.txt
```

### 2. Overlay Relocation
**Directory structure**:
```
# Before
/boot/overlays/iotg-rpi4/*.dtbo

# After
/boot/firmware/overlays/iotg-rpi4/*.dtbo
```

### 3. Version Update
- Version changed from `1.3-1` to `1.3-1buster1`

## Installation

On Debian Buster or later systems:

```bash
sudo dpkg -i iotg-rpi4-config_1.3-1buster1_all.deb
```

The package will:
1. Install device tree overlays to `/boot/firmware/overlays/iotg-rpi4/`
2. Install configuration utilities to `/usr/local/bin/`
3. Install systemd service for IE module detection
4. Install udev rules for CAN and TTY devices
5. Run the configuration utility in quiet mode

## Usage

After installation, run the configuration utility:

```bash
sudo iotg-rpi4-config
```

This provides an interactive menu to:
- Configure Industrial I/O modules (slots A, B, C, D)
- Enable/disable TPM
- Detect currently installed modules
- Apply configuration changes to `/boot/firmware/config.txt`

## Technical Details

### How It Works
1. The utility detects installed IE modules via GPIO expanders
2. User configures desired module types (CAN, RS232, RS485, Digital I/O)
3. Configuration is written to `/boot/firmware/config.txt` as dtoverlay entries:
   ```
   dtoverlay=iotg-rpi4/iotg-rpi4-ie-a,can
   dtoverlay=iotg-rpi4/iotg-rpi4-ie-b,uart
   ```
4. After reboot, the firmware loads the appropriate overlays

### Compatibility
- Device tree overlay syntax remains unchanged (relative paths)
- All functionality preserved from original package
- Works with Raspberry Pi OS (Debian Buster/Bullseye/Bookworm)

## Repackaging

To repackage again or modify further, use the included script:

```bash
python3 repackage_for_buster.py
```

This automates the extraction, modification, and repackaging process.