Changes to underlying libraries (gf180mcu klayout pcell device
updates, ngspice model fixes ("nf" and "m" positions moved forward
in all pin lists) and the sky130 precheck are sufficient to
warrant a new repository reference set ("make reference").
diff --git a/VERSION b/VERSION
index afa3e05..16700f9 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.0.550
+1.0.551
diff --git a/gf180mcu/gf180mcu.json b/gf180mcu/gf180mcu.json
index 7a2dc66..6c7b89d 100644
--- a/gf180mcu/gf180mcu.json
+++ b/gf180mcu/gf180mcu.json
@@ -94,16 +94,16 @@
         "magic": "MAGIC_COMMIT"
     },
     "reference": {
-        "open_pdks": "0536d02d875c8f67dd7cca3902ac457e62f20005",
-        "magic": "b1c7b52ed2762cda743c9cc6cc6e16fabcfe8073",
+        "open_pdks": "6971617b18b2f322d8f574af7e53f79ddd75dafe",
+        "magic": "0e84616af8ab2389e75e49191a29a145873d068c",
         "gf180mcu_pdk": "a897aa30369d3bcec87d9d50ce9b01f320f854ef",
-        "gf180mcu_fd_pr": "13e4b0e81d1a3c993c603a286b939afe70c52cc9",
+        "gf180mcu_fd_pr": "9e18ebaf6e71702a618c6fb85f488af93ce773ad",
         "gf180mcu_fd_pv": "10ee7fc75437edafa56f29f2b1872e95c9f22b71",
         "gf180mcu_fd_io": "545621fdbac44f55344834e6c03486310c0862d7",
         "gf180mcu_fd_sc_mcu7t5v0": "8743b6f9641eb8707179c4e51703380d4dc90f16",
         "gf180mcu_fd_sc_mcu9t5v0": "e0e80f5a6522f10b82165d3aeab9b8ee28e89849",
         "gf180mcu_fd_ip_sram": "9c411928870ce15226228fa52ddb6ecc0ea4ffbe",
-        "gf180mcu_as_sc_mcu7t3v3": "450f6039f6d7f556b47f74b456c010f424d9cfcd",
+        "gf180mcu_as_sc_mcu7t3v3": "51f4e2a6d9692f3f8982dffaf7c012272a4b4ca3",
         "gf180mcu_ocd_io": "289e06e35aea55761b998cb6d13f7e70694f05fe",
         "gf180mcu_ocd_alpha": "076bab7ac11118e1aa810ccf75e5c297b5501fcc",
         "gf180mcu_osu_sc_gf12t3v3": "aa2fa8cd1bcb8fe98669acd05c0b0c65879268b3",
diff --git a/sky130/sky130.json b/sky130/sky130.json
index 1d0c644..5f10230 100644
--- a/sky130/sky130.json
+++ b/sky130/sky130.json
@@ -94,8 +94,8 @@
         "magic": "MAGIC_COMMIT"
     },
     "reference": {
-        "open_pdks": "0536d02d875c8f67dd7cca3902ac457e62f20005",
-        "magic": "b1c7b52ed2762cda743c9cc6cc6e16fabcfe8073",
+        "open_pdks": "6971617b18b2f322d8f574af7e53f79ddd75dafe",
+        "magic": "0e84616af8ab2389e75e49191a29a145873d068c",
         "sky130_fd_pr": "1232782c1b9fab3aacda74d67ce7c92bf7da8105",
         "sky130_fd_io": "e60737bf624df95c211fe99c007ddec78e3e081d",
         "sky130_fd_sc_hs": "c4cfcd760f1964f1670a1ed99c71c7c12b7ad49f",
@@ -114,6 +114,6 @@
         "sky130_ml_xx_hd": "6eb3b0718552b034f1bf1870285ff135e3fb2dcb",
         "xschem_sky130": "7d19acb9fc9c54f6de86345e454dc59e57418a26",
         "klayout_sky130": "9861f40ff389c86fbe082122ee868a065cd4cfd4",
-        "precheck_sky130": "7eb869a4b6a5807f49d5ae738c541cce39c41ba5"
+        "precheck_sky130": "86b7362dacd931bf1fd957c84501bfbe7955fa7c"
     }
 }