diff --git a/node/rustchain_v2_integrated_v2.2.1_rip200.py b/node/rustchain_v2_integrated_v2.2.1_rip200.py
index 8af0d63..95d449f 100644
--- a/node/rustchain_v2_integrated_v2.2.1_rip200.py
+++ b/node/rustchain_v2_integrated_v2.2.1_rip200.py
@@ -1023,8 +1023,7 @@ def validate_fingerprint_data(fingerprint: dict, claimed_device: dict = None) ->
     - C miner format: {"checks": {"clock_drift": true}}
     """
     if not fingerprint:
-        # Legacy miners without fingerprint get reduced weight (not zero, not full)
-        return True, "no_fingerprint_data_legacy_reduced"
+        return False, "missing_fingerprint_data"
 
     checks = fingerprint.get("checks", {})
     claimed_device = claimed_device or {}
@@ -1079,6 +1078,8 @@ def get_check_status(check_data):
         if clock_check.get("passed") == True and samples == 0 and cv == 0:
             print(f"[FINGERPRINT] REJECT: clock_drift claims pass but no samples/cv")
             return False, "clock_drift_no_evidence"
+        if clock_check.get("passed") == True and samples < 32:
+            return False, f"clock_drift_insufficient_samples:{samples}"
 
         if cv < 0.0001 and cv != 0:
             return False, "timing_too_uniform"
@@ -1888,8 +1889,8 @@ def submit_attestation():
             return jsonify(oui_info), 412
 
     # NEW: Validate fingerprint data (RIP-PoA)
-    fingerprint_passed = True
-    fingerprint_reason = "not_checked"
+    fingerprint_passed = False
+    fingerprint_reason = "missing_fingerprint_data"
 
     if fingerprint:
         fingerprint_passed, fingerprint_reason = validate_fingerprint_data(fingerprint, claimed_device=device)
@@ -1900,12 +1901,15 @@ def submit_attestation():
         if not fingerprint_passed:
             # VM/emulator detected - allow attestation but with zero weight
             print(f"[FINGERPRINT] VM/EMULATOR DETECTED - will receive ZERO rewards")
+    else:
+        print(f"[FINGERPRINT] Missing fingerprint payload for miner {miner} - zero reward weight")
 
     # NEW: Server-side VM check (double-check device/signals)
     vm_ok, vm_reason = check_vm_signatures_server_side(device, signals)
     if not vm_ok:
         print(f"[VM_CHECK] Miner: {miner} - VM DETECTED (zero rewards): {vm_reason}")
         fingerprint_passed = False  # Mark as failed for zero weight
+        fingerprint_reason = f"server_vm_check_failed:{vm_reason}"
 
     # Record successful attestation (with fingerprint status)
     record_attestation_success(miner, device, fingerprint_passed, client_ip)
@@ -1978,6 +1982,7 @@ def submit_attestation():
         "status": "accepted",
         "device": device,
         "fingerprint_passed": fingerprint_passed,
+        "fingerprint_reason": fingerprint_reason,
         "macs_recorded": len(macs) if macs else 0
     })
 
diff --git a/tests/test_fingerprint.py b/tests/test_fingerprint.py
index a41e8e9..dbd3637 100644
--- a/tests/test_fingerprint.py
+++ b/tests/test_fingerprint.py
@@ -31,10 +31,10 @@ def test_compute_hardware_id_consistency():
     assert id1 == id2
 
 def test_validate_fingerprint_data_no_data():
-    """Verify handling of missing fingerprint data (legacy reduced)."""
+    """Missing fingerprint payload must fail validation."""
     passed, reason = validate_fingerprint_data(None)
-    assert passed is True
-    assert reason == "no_fingerprint_data_legacy_reduced"
+    assert passed is False
+    assert reason == "missing_fingerprint_data"
 
 def test_validate_fingerprint_data_vm_detection():
     """Verify detection of VM indicators."""
@@ -78,6 +78,20 @@ def test_validate_fingerprint_data_clock_drift_threshold():
     assert passed is False
     assert reason == "timing_too_uniform"
 
+def test_validate_fingerprint_data_clock_drift_insufficient_samples():
+    """Clock drift cannot pass with extremely low sample count."""
+    fingerprint = {
+        "checks": {
+            "clock_drift": {
+                "passed": True,
+                "data": {"cv": 0.02, "samples": 1}
+            }
+        }
+    }
+    passed, reason = validate_fingerprint_data(fingerprint)
+    assert passed is False
+    assert reason.startswith("clock_drift_insufficient_samples")
+
 def test_validate_fingerprint_data_vintage_stability():
     """Verify rejection of suspicious stability on vintage hardware."""
     claimed_device = {"device_arch": "G4"}