@Capsia Thank You! 🙂
I'll continue searching but now with proper tools.
For more advanced users maybe this or this will help - Especially this part of article: "Here is an example script of modem initialization:(...)"
@doniks its just a .img file contained in a .gz
just extract the .gz file and flash the resulting image onto a USB drive (or a harddrive depending on if you'd wanna install it as main os)
@ali461 you're welcome!