diff --git a/lib/src/types/default.nix b/lib/src/types/default.nix
index 7582f9a..4251e86 100644
--- a/lib/src/types/default.nix
+++ b/lib/src/types/default.nix
@@ -820,6 +820,7 @@ lib: {
           check = value: builtins.isAttrs value || builtins.isFunction value || lib.types.path.check value;
           merge = location: definitions: let
             result = base.extend {
+              prefix = location;
               modules =
                 [{config.__module__.args.dynamic.name = lib.lists.last location;}]
                 ++ getModules definitions;
diff --git a/tidepool/src/lib/systems.nix b/tidepool/src/lib/systems.nix
index b97109c..24d31c9 100644
--- a/tidepool/src/lib/systems.nix
+++ b/tidepool/src/lib/systems.nix
@@ -2103,7 +2103,7 @@ in {
               then "x86" # not i386
               else if resolved.isMips64
               then "mips64" # uboot *does* distinguish between mips32/mips64
-              else resolved.linuxArch; # other cases appear to agree with linuxArch
+              else resolved.linux.arch # other cases appear to agree with linuxArch
 
             qemu.arch =
               if resolved.isAarch32