diff --git a/ice40/constids.inc b/ice40/constids.inc
index 5575053d..89b3bacd 100644
--- a/ice40/constids.inc
+++ b/ice40/constids.inc
@@ -615,3 +615,4 @@ X(u2k)
 X(u4k)
 X(up3k)
 X(up5k)
+X(noglobal)
diff --git a/ice40/pack.cc b/ice40/pack.cc
index fd0990a5..119568f5 100644
--- a/ice40/pack.cc
+++ b/ice40/pack.cc
@@ -680,13 +680,13 @@ static void insert_global(Context *ctx, NetInfo *net, bool is_reset, bool is_cen
 static void promote_globals(Context *ctx)
 {
     log_info("Promoting globals..\n");
-    const int logic_fanout_thresh = 15;
-    const int enable_fanout_thresh = 15;
-    const int reset_fanout_thresh = 15;
+    const int logic_fanout_thresh = 40;
+    const int enable_fanout_thresh = 40;
+    const int reset_fanout_thresh = 40;
     std::map<IdString, int> clock_count, reset_count, cen_count, logic_count;
     for (auto &net : ctx->nets) {
         NetInfo *ni = net.second.get();
-        if (ni->driver.cell != nullptr && !ctx->is_global_net(ni)) {
+        if (ni->driver.cell != nullptr && !ctx->is_global_net(ni) && !bool_or_default(ni->attrs, id_noglobal)) {
             clock_count[net.first] = 0;
             reset_count[net.first] = 0;
             cen_count[net.first] = 0;