komiter Hi there, thanks for taking the time to share this.
My concern with such an approach is that the install guides do regularly change and get updated and your flashing script is unlikely to be maintained in accordance with that.
The only recommended ways to install GrapheneOS are the official install guides. The web installer is recommended over the CLI installer, since it's easier to use, and there's less that can go wrong.
Next time you use the web installer, and if you have any issues, please join the GrapheneOS chatroom on Matrix, and the community will help you get it working: https://matrix.to/#/#grapheneos:grapheneos.org
For these reasons, I have removed the link from your post.