diff --git a/systemc-components/common/include/qkmulti-quantum.h b/systemc-components/common/include/qkmulti-quantum.h
index 521994d1..4eca03d0 100644
--- a/systemc-components/common/include/qkmulti-quantum.h
+++ b/systemc-components/common/include/qkmulti-quantum.h
@@ -20,8 +20,15 @@ class tlm_quantumkeeper_multi_quantum : public tlm_quantumkeeper_multithread
         sc_core::sc_time quantum = tlm_utils::tlm_quantumkeeper::get_global_quantum();
         sc_core::sc_time next_quantum_boundary = sc_core::sc_time_stamp() + quantum;
         sc_core::sc_time now = get_current_time();
-        if (next_quantum_boundary >= now) {
+        if (now < next_quantum_boundary) {
             return next_quantum_boundary - now;
+        } else if (now == next_quantum_boundary) {
+            // At the exact boundary: the CPU has used its quantum but hasn't
+            // exceeded it. Return a minimal non-zero value so sync() doesn't
+            // block. The timehandler will advance the kernel on the next delta
+            // cycle; blocking here risks a deadlock when sc_suspend_all()
+            // prevents next_time() from seeing the scheduled tick event.
+            return sc_core::sc_time(1, sc_core::SC_PS);
         } else {
             return sc_core::SC_ZERO_TIME;
         }