NixOS Package

[dragonlord]

That's really not nice. It's a security feature to avoid file corruption and tampering. But you could disable the checks in if nothing helps:
- https://github.com/LordOfDragons/dragen ... e.cpp#L548
- https://github.com/LordOfDragons/dragen ... n.cpp#L390
You would need to disable the entire if-blocks there to avoid the file based exception.

[gale_username]

Is there a way I could generate the manifest files separate from the main build step after the modules have been patched?

[dragonlord]

The manifest files are XML files. You can use an XML library to load, edit and save them. Most probably simpler would be using an XSLT processor to alter a specific tag content. "xsltproc" is the usual command line tool to do this.