diff --git a/nodes/pip/main.cpp b/nodes/pip/main.cpp
index d9d55a3..580ba61 100644
--- a/nodes/pip/main.cpp
+++ b/nodes/pip/main.cpp
@@ -131,10 +131,13 @@ class PiPNode : public dmf::NodeBase {
                 uint8_t* bg_buf    = nullptr;
                 uint8_t* inset_buf = nullptr;
 
-                const mxlStatus bg_st = mxlFlowReaderGetGrainNonBlocking(
-                    bg_reader,    index, &bg_grain,    &bg_buf);
-                const mxlStatus in_st = mxlFlowReaderGetGrainNonBlocking(
-                    inset_reader, index, &inset_grain, &inset_buf);
+                // Use blocking reads: sync group returns OK when headIndex >= expectedIndex,
+                // but the writer may not have set validSlices yet. Blocking read handles
+                // that race by waiting for validSlices == totalSlices.
+                const mxlStatus bg_st = mxlFlowReaderGetGrain(
+                    bg_reader,    index, 40'000'000, &bg_grain, &bg_buf);
+                const mxlStatus in_st = mxlFlowReaderGetGrain(
+                    inset_reader, index, 40'000'000, &inset_grain, &inset_buf);
 
                 if (bg_st != MXL_STATUS_OK || in_st != MXL_STATUS_OK || !bg_buf || !inset_buf) {
                     log("grain read after sync OK: bg=%s inset=%s at index=%llu",