I have noticed (by the laptop not booting…) that Gentoo now offers binary packages for gentoo-sources. However, binary packages cannot apply user-patches, so if one is using user-patches to patch the gentoo-sources kernel for the Reform, this now needs a configuration change to block the binary packages for gentoo-sources.
This can be done with the --usepkg-exclude switch, as shown in the Binary package guide on the Gentoo Wiki.