flake: add nixpkgs-unstable for u-boot

flake.lock

@@ -18,11 +18,27 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1700390070,
-        "narHash": "sha256-de9KYi8rSJpqvBfNwscWdalIJXPo8NjdIZcEJum1mH0=",
+        "lastModified": 1701053011,
+        "narHash": "sha256-8QQ7rFbKFqgKgLoaXVJRh7Ik5LtI3pyBBCfOnNOGkF0=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "e4ad989506ec7d71f7302cc3067abd82730a4beb",
+        "rev": "5b528f99f73c4fad127118a8c1126b5e003b01a9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-23.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1700794826,
+        "narHash": "sha256-RyJTnTNKhO0yqRpDISk03I/4A67/dp96YRxc86YOPgU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "5a09cb4b393d58f9ed0d9ca1555016a8543c2ac8",
         "type": "github"
       },
       "original": {
@@ -32,24 +48,12 @@
         "type": "github"
       }
     },
-    "nixpkgs_2": {
-      "locked": {
-        "lastModified": 1697730408,
-        "narHash": "sha256-Ww//zzukdTrwTrCUkaJA/NsaLEfUfQpWZXBdXBYfhak=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "ff0a5a776b56e0ca32d47a4a47695452ec7f7d80",
-        "type": "github"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
-      }
-    },
     "not-os": {
       "inputs": {
         "firmware": "firmware",
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
         "lastModified": 1699416673,
@@ -68,6 +72,7 @@
     "root": {
       "inputs": {
         "nixpkgs": "nixpkgs",
+        "nixpkgs-unstable": "nixpkgs-unstable",
         "not-os": "not-os"
       }
     }