# OS Image Flashing on SD-card
To flash an image on a SD-card it is required to have a PC with:
  - SD-card slot
  - Z-standard decompression tool
1. Download desired OS Image from {{ espros_download_link }}. Refer to \<Product\>-vYYYY.MM.DD.img.zst
   ```{warning} Ensure the image matches the desired hardware. A missmatch might lead to defects. 
   ```
2. Decompress image file:
   -  Windows:
      -  Right-click -> extract all...
   -  Linux & MacOs in shell:
      -  ```bash
         zstd -d <image-path>
         ```
3. Insert SD-card into PC
4. Follow instructions on the raspberry pi guide {{ rpi_os_install_link }}
   - Select "**Use Custom**" in Step 2.2 and select the decompressed image
   - Skip Step 3 completely as the custom OS does not support configuration
5. The SD-card may be inserted into the unpowered raspberry pi
6. Power the raspberry pi. On first boot the image will install packages and reboot by itself. This may take a few minutes. 
```{important} **Do not unpower or have any kind of input during very first boot after flashing or you may put your flashed image in an unstable state!**<br>
If this happens re-flash the image.
```