diff --git a/common/place_common.cc b/common/place_common.cc
index b02904ec..0b7a0352 100644
--- a/common/place_common.cc
+++ b/common/place_common.cc
@@ -189,9 +189,15 @@ class ConstraintLegaliseWorker
                 diameter = 1;
             } else if (sign == -1) {
                 sign = 1;
+                if ((start + sign * diameter) > max)
+                    sign = -1;
                 ++diameter;
             } else {
                 sign = -1;
+                if ((start + sign * diameter) > max) {
+                    sign = 1;
+                    ++diameter;
+                }
             }
         }
 
diff --git a/common/placer1.cc b/common/placer1.cc
index 3a25f42c..d3665eb6 100644
--- a/common/placer1.cc
+++ b/common/placer1.cc
@@ -224,7 +224,7 @@ class SAPlacer
             // Once cooled below legalise threshold, run legalisation and start requiring
             // legal moves only
             if (temp < legalise_temp && !require_legal) {
-                // legalise_design(ctx);
+                legalise_relative_constraints(ctx);
                 // FIXME
                 require_legal = true;
                 autoplaced.clear();
@@ -294,7 +294,7 @@ class SAPlacer
             }
             BelType targetType = ctx->belTypeFromId(cell->type);
             for (auto bel : ctx->getBels()) {
-                if (ctx->getBelType(bel) == targetType && (ctx->isValidBelForCell(cell, bel) || !require_legal)) {
+                if (ctx->getBelType(bel) == targetType && ctx->isValidBelForCell(cell, bel)) {
                     if (ctx->checkBelAvail(bel)) {
                         uint64_t score = ctx->rng64();
                         if (score <= best_score) {
@@ -364,15 +364,14 @@ class SAPlacer
         if (other != IdString()) {
             ctx->bindBel(oldBel, other_cell->name, STRENGTH_WEAK);
         }
-        if (require_legal) {
-            if (!ctx->isBelLocationValid(newBel) || ((other != IdString() && !ctx->isBelLocationValid(oldBel)))) {
-                ctx->unbindBel(newBel);
-                if (other != IdString())
-                    ctx->unbindBel(oldBel);
-                goto swap_fail;
-            }
+        if (!ctx->isBelLocationValid(newBel) || ((other != IdString() && !ctx->isBelLocationValid(oldBel)))) {
+            ctx->unbindBel(newBel);
+            if (other != IdString())
+                ctx->unbindBel(oldBel);
+            goto swap_fail;
         }
 
+
         new_metric = curr_metric;
 
         // Recalculate metrics for all nets touched by the peturbation
diff --git a/ice40/chains.cc b/ice40/chains.cc
index 5b834c07..b1ad1007 100644
--- a/ice40/chains.cc
+++ b/ice40/chains.cc
@@ -277,6 +277,6 @@ class ChainConstrainer
     void constrain_chains() { process_carries(); }
 };
 
-void constrain_chains(Context *ctx) { ChainConstrainer(ctx).constrain_chains(); }
+void constrain_chains(Context *ctx) { log_info("Constraining chains...\n"); ChainConstrainer(ctx).constrain_chains(); }
 
 NEXTPNR_NAMESPACE_END
diff --git a/ice40/pack.cc b/ice40/pack.cc
index fc182e98..9700bc5d 100644
--- a/ice40/pack.cc
+++ b/ice40/pack.cc
@@ -26,6 +26,7 @@
 #include "design_utils.h"
 #include "log.h"
 #include "util.h"
+#include "chains.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
@@ -893,6 +894,8 @@ bool Arch::pack()
         pack_ram(ctx);
         pack_special(ctx);
         ctx->assignArchInfo();
+        constrain_chains(ctx);
+        ctx->assignArchInfo();
         log_info("Checksum: 0x%08x\n", ctx->checksum());
         return true;
     } catch (log_execution_error_exception) {