diff --git a/pkgs/development/tools/misc/hydra/eval.patch b/pkgs/development/tools/misc/hydra/eval.patch
deleted file mode 100644
index 0be856ee7570..000000000000
--- a/pkgs/development/tools/misc/hydra/eval.patch
+++ /dev/null
@@ -1,11 +0,0 @@
-diff --git a/src/hydra-eval-jobs/Makefile.am b/src/hydra-eval-jobs/Makefile.am
-index 7a4e9c91..90742a30 100644
---- a/src/hydra-eval-jobs/Makefile.am
-+++ b/src/hydra-eval-jobs/Makefile.am
-@@ -1,5 +1,5 @@
- bin_PROGRAMS = hydra-eval-jobs
- 
- hydra_eval_jobs_SOURCES = hydra-eval-jobs.cc
--hydra_eval_jobs_LDADD = $(NIX_LIBS)
-+hydra_eval_jobs_LDADD = $(NIX_LIBS) -lnixcmd
- hydra_eval_jobs_CXXFLAGS = $(NIX_CFLAGS) -I ../libhydra
diff --git a/pkgs/development/tools/misc/hydra/unstable.nix b/pkgs/development/tools/misc/hydra/unstable.nix
index 709af8f44855..db21e94d738a 100644
--- a/pkgs/development/tools/misc/hydra/unstable.nix
+++ b/pkgs/development/tools/misc/hydra/unstable.nix
@@ -126,16 +126,22 @@ let
 in
 stdenv.mkDerivation rec {
   pname = "hydra";
-  version = "2022-05-03";
+  version = "2022-06-16";
 
   src = fetchFromGitHub {
     owner = "NixOS";
     repo = "hydra";
-    rev = "7c133a98f8e689cdc13f8a1adaaa9cd75d039a35";
-    sha256 = "sha256-LqBLIXYssvDoSp2Hf2+vDDB9O8VSF48HAGwL8pI2WZY=";
+    rev = "fb26435fe9a54f13143e69a545b8f3cecffaed96";
+    sha256 = "sha256-kmgN7D7tUC3Ki70D+rdS19PW/lrANlU3tc8gu5gsld0=";
   };
 
-  patches = [ ./eval.patch ];
+  patches = [
+    # https://github.com/NixOS/hydra/pull/1215: scmdiff: Hardcode --git-dir
+    (fetchpatch {
+      url = "https://github.com/NixOS/hydra/commit/b6ea85a601ddac9cb0716d8cb4d446439fa0778f.patch";
+      sha256 = "sha256-QHjwLYQucdkBs6OsFI8kWo5ugkPXXlTgdbGFxKBHAHo=";
+    })
+  ];
 
   buildInputs =
     [
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index ee64afa86cf4..238e2537d2bf 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -18025,7 +18025,7 @@ with pkgs;
 
   hwloc = callPackage ../development/libraries/hwloc {};
 
-  hydra_unstable = callPackage ../development/tools/misc/hydra/unstable.nix { nix = nixVersions.nix_2_8; };
+  hydra_unstable = callPackage ../development/tools/misc/hydra/unstable.nix { nix = nixVersions.nix_2_9; };
 
   hydra-cli = callPackage ../development/tools/misc/hydra-cli { };