This script polls the IPSW.me API and builds a list of files for aria2 to download. To run this, you will need Ruby, and Aria2. Included are device.yml (device mappings), and firmwares.yml (device firmware URLs). Big thanks to IPSW.me for providing the API. If you want to update the device or firmware list simply remove both yml files and run the script again
This script was inspired by this post on r/jailbreak
Pull requests are welcome!