diff --git a/flake.lock b/flake.lock
index 5becd39..5401cba 100644
--- a/flake.lock
+++ b/flake.lock
@@ -4,18 +4,18 @@
       "inputs": {
         "artiq-comtools": "artiq-comtools",
         "mozilla-overlay": "mozilla-overlay",
-        "nixpkgs": "nixpkgs",
-        "sipyco": "sipyco",
+        "nixpkgs": "nixpkgs_3",
+        "sipyco": "sipyco_2",
         "src-migen": "src-migen",
         "src-misoc": "src-misoc",
         "src-pythonparser": "src-pythonparser"
       },
       "locked": {
-        "lastModified": 1652950139,
-        "narHash": "sha256-t+u0KQPnq+vGF9PhrGKMnj2BtknODijQYqAH9nufaSY=",
+        "lastModified": 1650337489,
+        "narHash": "sha256-pKS38KZKiibPHX57iwmlH7i3JqdVVK8HYkxeifRqsY0=",
         "ref": "master",
-        "rev": "cf8e5838474ed1c6f9252ad0caa0f2773c7e0565",
-        "revCount": 8053,
+        "rev": "58b59b99ff665860a5101075d4e2e2a47e35db43",
+        "revCount": 8030,
         "type": "git",
         "url": "https://github.com/m-labs/artiq.git"
       },
@@ -26,14 +26,8 @@
     },
     "artiq-comtools": {
       "inputs": {
-        "nixpkgs": [
-          "artiq",
-          "nixpkgs"
-        ],
-        "sipyco": [
-          "artiq",
-          "sipyco"
-        ]
+        "nixpkgs": "nixpkgs",
+        "sipyco": "sipyco"
       },
       "locked": {
         "lastModified": 1649124276,
@@ -52,11 +46,11 @@
     "mozilla-overlay": {
       "flake": false,
       "locked": {
-        "lastModified": 1650459918,
-        "narHash": "sha256-sroCK+QJTmoXtcRkwZyKOP9iAYOPID2Bwdxn4GkG16w=",
+        "lastModified": 1645464064,
+        "narHash": "sha256-YeN4bpPvHkVOpQzb8APTAfE7/R+MFMwJUMkqmfvytSk=",
         "owner": "mozilla",
         "repo": "nixpkgs-mozilla",
-        "rev": "e1f7540fc0a8b989fb8cf701dc4fd7fc76bcf168",
+        "rev": "15b7a05f20aab51c4ffbefddb1b448e862dccb7d",
         "type": "github"
       },
       "original": {
@@ -68,11 +62,11 @@
     "mozilla-overlay_2": {
       "flake": false,
       "locked": {
-        "lastModified": 1650459918,
-        "narHash": "sha256-sroCK+QJTmoXtcRkwZyKOP9iAYOPID2Bwdxn4GkG16w=",
+        "lastModified": 1645464064,
+        "narHash": "sha256-YeN4bpPvHkVOpQzb8APTAfE7/R+MFMwJUMkqmfvytSk=",
         "owner": "mozilla",
         "repo": "nixpkgs-mozilla",
-        "rev": "e1f7540fc0a8b989fb8cf701dc4fd7fc76bcf168",
+        "rev": "15b7a05f20aab51c4ffbefddb1b448e862dccb7d",
         "type": "github"
       },
       "original": {
@@ -99,11 +93,59 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1652559422,
-        "narHash": "sha256-jPVTNImBTUIFdtur+d4IVot6eXmsvtOcBm0TzxmhWPk=",
+        "lastModified": 1650244918,
+        "narHash": "sha256-DsS5nxjTpnoUC4pNXJI1rit7TnDTij8vQDa5PtcDCD0=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "8b3398bc7587ebb79f93dfeea1b8c574d3c6dba1",
+        "rev": "7b38b03d76ab71bdc8dc325e3f6338d984cc35ca",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1650244918,
+        "narHash": "sha256-DsS5nxjTpnoUC4pNXJI1rit7TnDTij8vQDa5PtcDCD0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7b38b03d76ab71bdc8dc325e3f6338d984cc35ca",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_3": {
+      "locked": {
+        "lastModified": 1650244918,
+        "narHash": "sha256-DsS5nxjTpnoUC4pNXJI1rit7TnDTij8vQDa5PtcDCD0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7b38b03d76ab71bdc8dc325e3f6338d984cc35ca",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_4": {
+      "locked": {
+        "lastModified": 1650244918,
+        "narHash": "sha256-DsS5nxjTpnoUC4pNXJI1rit7TnDTij8vQDa5PtcDCD0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7b38b03d76ab71bdc8dc325e3f6338d984cc35ca",
         "type": "github"
       },
       "original": {
@@ -122,17 +164,32 @@
     },
     "sipyco": {
       "inputs": {
-        "nixpkgs": [
-          "artiq",
-          "nixpkgs"
-        ]
+        "nixpkgs": "nixpkgs_2"
       },
       "locked": {
-        "lastModified": 1651624017,
-        "narHash": "sha256-engReD8l4xzQQJP8BJ7gILUyA1KH5d60lexDVfnoiRM=",
+        "lastModified": 1649724535,
+        "narHash": "sha256-15Nun4EY35j+6SPZkjzZtyH/ncxLS60KuGJjFh5kSTc=",
         "owner": "m-labs",
         "repo": "sipyco",
-        "rev": "efda015e9994faf6cafc19b239d8e69ca4d26226",
+        "rev": "939f84f9b5eef7efbf7423c735d1834783b6140e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "m-labs",
+        "repo": "sipyco",
+        "type": "github"
+      }
+    },
+    "sipyco_2": {
+      "inputs": {
+        "nixpkgs": "nixpkgs_4"
+      },
+      "locked": {
+        "lastModified": 1649724535,
+        "narHash": "sha256-15Nun4EY35j+6SPZkjzZtyH/ncxLS60KuGJjFh5kSTc=",
+        "owner": "m-labs",
+        "repo": "sipyco",
+        "rev": "939f84f9b5eef7efbf7423c735d1834783b6140e",
         "type": "github"
       },
       "original": {
@@ -200,11 +257,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1653445336,
-        "narHash": "sha256-xuwesRrQiccopPTCkwGqQxld74X74q7EVsKIrE0zirc=",
+        "lastModified": 1649317447,
+        "narHash": "sha256-7qRHEHg+CXqqZSLgV4j9XLrLj6mlaeXzCZ8eFkRa0U8=",
         "ref": "master",
-        "rev": "605c8f73a60cf41a6e2d535c5850933d3154e935",
-        "revCount": 616,
+        "rev": "56c27e98e4fc2bd719d26abaa98a7628c395b9c0",
+        "revCount": 615,
         "type": "git",
         "url": "https://git.m-labs.hk/m-labs/zynq-rs"
       },