diff --git a/ops/nixos/lib/zfs.nix b/ops/nixos/lib/zfs.nix
index 78708bf2fa..a734233f5b 100644
--- a/ops/nixos/lib/zfs.nix
+++ b/ops/nixos/lib/zfs.nix
@@ -25,8 +25,8 @@ in
     };
 
     boot.initrd.postDeviceCommands = mkIf robCfg.enable
-      mkAfter ''
+      (mkAfter ''
         zfs rollback -r ${robCfg.snapshot}
-      '';
+      '');
   };
 }
diff --git a/ops/nixos/marukuru/default.nix b/ops/nixos/marukuru/default.nix
index e638928671..1e2c7bab54 100644
--- a/ops/nixos/marukuru/default.nix
+++ b/ops/nixos/marukuru/default.nix
@@ -142,8 +142,5 @@ in {
     };
   };
 
-  boot.kernel.sysctl."net.ipv4.tcp_congestion_control" = "bbr";
-  boot.kernel.sysctl."net.core.default_qdisc" = "fq_codel";
-
   system.stateVersion = "20.03";
 }