I have a simple material with a texture applied to an object. When I update the texture I have to restart Houdini everytime to see the updated version of the texture. Is there a way to do this without restarting Houdini? I tried “textcache -c” in textport, but no result.

Sounds a bit like viewport or driver issue. You can try to delete the current Scene View (click the little x). Then add a new Scene View back to your project. This can avoid a complete restart, perhaps?

I knew it had to be super simple!

Render -> Update Textures

That's all. If now someone could explain why I am not allowed to map a keyboard shortcut to this function I'd be super interested to hear it.

I'd love to have a keyboard map to toggle between AutoUpdate and Manual.

Is there any python command that let you update texture, maybe only for specific objects?