diff --git a/contrib/offline-replay/run_offline_replay_backtest.sh b/contrib/offline-replay/run_offline_replay_backtest.sh
index 688c9dfcf4d..312d92a2ecd 100755
--- a/contrib/offline-replay/run_offline_replay_backtest.sh
+++ b/contrib/offline-replay/run_offline_replay_backtest.sh
@@ -316,7 +316,11 @@ build_firedancer() {
     EXTRAS=offline-replay make -j
 
     OBJDIR=$(EXTRAS=offline-replay make --silent --no-print-directory objdir 2>/dev/null || true)
-    : "${OBJDIR:?cannot determine OBJDIR (make objdir failed)}"
+    if [ -z "$OBJDIR" ] || [ ! -x "$OBJDIR/bin/firedancer-dev" ]; then
+        send_slack_message "@here offline-replay: firedancer-dev not found at \`${OBJDIR:-<unresolved>}/bin\` after build (OBJDIR/build-config mismatch, not a ledger failure). Exiting."
+        exit 1
+    fi
+    export OBJDIR
 }
 
 # Convert the downloaded rocksdb into a shredcap capture covering the replay
@@ -614,6 +618,7 @@ replay_until_clean() {
         # config, permissions, ...) — that is an infrastructure problem, not
         # a ledger mismatch, so there is nothing to minimize.
         if [ "$status" -ne 0 ] && [ ! -s "$TEMP_LOG" ]; then
+            sudo -E $OBJDIR/bin/firedancer-dev configure fini all --config $LEDGER_DIR/offline_replay.toml &> /dev/null || true
             send_slack_message "@here Backtest produced no log output; firedancer-dev likely failed at startup. See the configure output in the harness log. Exiting."
             exit 1
         fi
diff --git a/src/flamenco/runtime/tests/run_ledger_backtest.sh b/src/flamenco/runtime/tests/run_ledger_backtest.sh
index b35b90e0a92..2fe09ad3edb 100755
--- a/src/flamenco/runtime/tests/run_ledger_backtest.sh
+++ b/src/flamenco/runtime/tests/run_ledger_backtest.sh
@@ -294,6 +294,8 @@ fi
 
 echo_notice "Running backtest for $LEDGER"
 
+[ -x "$OBJDIR/bin/firedancer-dev" ] || { echo "error: firedancer-dev not found at \"$OBJDIR/bin\" -- build it, or set OBJDIR/EXTRAS" >&2; exit 1; }
+
 sudo killall firedancer-dev &> /dev/null || true
 
 set -x
@@ -325,6 +327,9 @@ if [ "$status" -eq 0 ]; then
   exit 0
 fi
 
+if [ -z "$CI" ] && grep -q "Unable to set the thread affinity" "$LOG"; then
+  $OBJDIR/bin/firedancer-dev configure fini all --config ${DUMP_DIR}/${LEDGER}_backtest.toml &> /dev/null || true
+fi
 tail -n 10 $LOG
 echo "Failed with status: $status"