diff --git a/lib/fusesocLib.nix b/lib/fusesocLib.nix
index 8ef707e..28b6163 100644
--- a/lib/fusesocLib.nix
+++ b/lib/fusesocLib.nix
@@ -128,7 +128,7 @@ rec {
     in
     if (isNull stripped) then cond else builtins.head stripped;
 
-  resolveDeps = import ./resolveDeps.nix { inherit lib parseDependency; };
+  resolveDeps = import ./resolveDeps.nix { inherit lib parseDependency unique; };
 
   fetchProvider =
     core: hash:
@@ -187,6 +187,18 @@ rec {
     }
     .${provider.name} or (throw "Unknown provider name: ${provider.name}");
 
+  # uniquify by vlnv
+  unique =
+    coreList:
+    lib.mapAttrsToList (_: v: v) (
+      builtins.listToAttrs (
+        map (x: {
+          inherit (x.core) name;
+          value = x;
+        }) coreList
+      )
+    );
+
   addCore =
     prevSet: coreDrv:
     let
diff --git a/lib/resolveDeps.nix b/lib/resolveDeps.nix
index b95557c..f242e3e 100644
--- a/lib/resolveDeps.nix
+++ b/lib/resolveDeps.nix
@@ -1,6 +1,7 @@
 {
   lib,
   parseDependency,
+  unique,
 }:
 let
   parseDeps =
@@ -11,15 +12,28 @@ let
 
   fetchDepsShallow =
     coreDrv: coreSet:
-    map (
-      req:
-      let
-        core = coreSet.${req.vendor}.${req.library}.${req.name};
-        default = core; # toplevel derivation is always the latest version
-        candidates = core.list;
-      in
-      lib.findFirst (dep: req.condition dep.version) default candidates
-    ) (parseDeps coreDrv);
+    builtins.filter (x: !(isNull x)) (
+      map (
+        req:
+        let
+          existing = builtins.filter (
+            dep:
+            ({ inherit (dep.parsed) vendor library name; } == { inherit (req) vendor library name; })
+            && (req.condition dep.version)
+          ) coreDrv.dependencies;
+        in
+        if existing != [ ] then
+          # Use existing dependency if already set
+          (builtins.head existing)
+        else
+          (lib.findFirst (dep: req.condition dep.version) null (
+            coreSet.${req.vendor}.${req.library}.${req.name}.list or (lib.warn
+              "unable to find suitable dependency ${req.vendor}:${req.library}:${req.name} for core ${coreDrv.parsed.vendor}:${coreDrv.parsed.library}:${coreDrv.parsed.name}:${coreDrv.version}"
+              [ ]
+            )
+          ))
+      ) (parseDeps coreDrv)
+    );
 
   fetchDepsRecursive =
     coreDrv: coreSet:
@@ -28,17 +42,5 @@ let
     in
     deps ++ (builtins.concatMap (dep: fetchDepsRecursive dep coreSet) deps);
 
-  # uniquify by vlnv
-  unique =
-    coreList:
-    lib.mapAttrsToList (_: v: v) (
-      builtins.listToAttrs (
-        map (x: {
-          inherit (x.core) name;
-          value = x;
-        }) coreList
-      )
-    );
-
 in
 coreDrv: coreSet: unique (fetchDepsRecursive coreDrv coreSet)