If you set up crossdev, it adds a category, for examle cross-avr/, and adds it to /etc/portage/categories. Then if you try to `egencache --repo=local --update cross-avr/binutils --update-use-local-desc --verbose` you get this: !!! 'cross-avr/binutils' has a category that is not listed in /etc/portage/categories No ebuilds or cache entries found for 'cross-avr/binutils' And no metadata gets generated for the category. Moreover, if you don't speicify the [ATOM] for --update, egencache skips it with no error message, which makes troubleshooting tricky. Adding `cross-avr` to ::local/profiles/categories satisfies egencache and metadata gets generated.