### Requirements

1. Bootloader unlocked device
2. ADB and Fastboot installed on PC
3. Correct USB drivers installed
4. Battery level above 20%
5. Compatible GSI file in `.img.xz` format
6. Basic knowledge of Fastboot/ADB commands

---

### Step 1: Verify Device Compatibility

* Ensure the device supports **Project Treble**.
* Check architecture:

  * arm / arm64
* Check partition type:

  * A-only or A/B
* Confirm correct GSI variant for your device.

---

### Step 2: Extract the GSI Image

The downloaded file will be compressed as `.img.xz`.

Use the following command:

```
xz -d filename.img.xz
```

You will get:

```
filename.img
```

---

### Step 3: Boot Device into Fastboot Mode

1. Power off the device.
2. Hold the **Volume Down + Power** button (may vary by device).
3. Connect the device to PC via USB.

Verify connection:

```
fastboot devices
```

---

### Step 4: Disable Android Verified Boot (Recommended)

```
fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img
```

(Use stock vbmeta if available for your device.)

---

### Step 5: Wipe Existing Data

```
fastboot erase system
fastboot erase userdata
fastboot erase metadata
```

---

### Step 6: Flash the GSI Image

```
fastboot flash system filename.img
```

For dynamic partition devices:

```
fastboot flash system_a filename.img
```

or

```
fastboot flash system_b filename.img
```

---

### Step 7: Format Data

```
fastboot -w
```

---

### Step 8: Reboot Device

```
fastboot reboot
```

First boot may take 5–15 minutes.

---