diff --git a/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_dru b/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_dru
index 96403a9..362e232 100644
--- a/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_dru
+++ b/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_dru
@@ -1,4 +1,48 @@
 (version 1)
+
+# hbox-watchdog v4 — design rules
+#
+# Why three rules instead of one blanket minimum:
+#
+# The old file was a single unconditional (min 0.15mm).  A custom rule outranks
+# the netclass table, and an unconditional rule matches EVERY pair on the board,
+# so it was silently overriding the HV24 netclass's 0.5 mm clearance everywhere.
+# The netclass said 0.5; DRC was only ever enforcing 0.15.
+#
+# These three are mutually exclusive on the case that matters, so they give the
+# same answer whether KiCad resolves by rule order or by specificity:
+#
+#   1. neither item is HV24                       -> 0.15 mm  (unchanged)
+#   2. either item is HV24                        -> 0.50 mm
+#   3. except U2 pad-to-pad, its own land pattern -> 0.15 mm
+#
+# Rule 3 exists for exactly one pair.  U2 is the MP1584EN buck (SOIC-8-EP):
+# pad 7 (24V, 1.95 x 0.6) to pad 9 (the 2.29 x 3.0 exposed thermal pad, GND) is
+# 0.355 mm, and that is the manufacturer's qualified land pattern — it is set by
+# the package, not by routing, so no amount of rerouting can open it.  Scoping
+# the exception to Pad-to-Pad inside U2 keeps it from relaxing anything else:
+# measured on this board, U2's courtyard contains 9 pads and all 9 belong to U2,
+# so this condition cannot match a foreign pad.  The tracks and vias that pass
+# through that courtyard are excluded by the A.Type/B.Type test and stay at the
+# full 0.5 mm.
+#
+# HV24 = /24V_IN, 24V, IGN_IN, Q10_GATE  (netclass_patterns in the .kicad_pro)
+#
+# Note: raising HV24 to 0.5 mm also widens the copper pour pullback around those
+# nets, because a zone floods to max(its own clearance, the effective DRC
+# clearance) — 0.3 mm before, 0.5 mm now.  Press B to refill before running DRC.
+
 (rule "Minimum clearance 1"
 	(constraint clearance (min 0.15mm))
+	(condition "A.NetClass != 'HV24' && B.NetClass != 'HV24'")
+)
+
+(rule "HV24 clearance"
+	(constraint clearance (min 0.5mm))
+	(condition "(A.NetClass == 'HV24' || B.NetClass == 'HV24') && !(A.Type == 'Pad' && B.Type == 'Pad' && A.memberOfFootprint('U2') && B.memberOfFootprint('U2'))")
+)
+
+(rule "HV24 exception: MP1584EN land pattern"
+	(constraint clearance (min 0.15mm))
+	(condition "A.Type == 'Pad' && B.Type == 'Pad' && A.memberOfFootprint('U2') && B.memberOfFootprint('U2')")
 )
diff --git a/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_pcb b/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_pcb
index f4b60b4..cc70403 100644
--- a/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_pcb
+++ b/03-Architecture-Hardware/kicad/hbox-watchdog-v4.kicad_pcb
@@ -58999,7 +58999,7 @@
 		(uuid "357fbcc3-4ce7-4abb-9b6e-fa375f12652e")
 	)
 	(segment
-		(start 191.79 92.1)
+		(start 192.34 92.1)
 		(end 191.79 91.51)
 		(width 1)
 		(layer "F.Cu")
@@ -59023,8 +59023,8 @@
 		(uuid "6df4c8df-a9ee-47a1-b804-5b5569776a32")
 	)
 	(segment
-		(start 194.53 94.84)
-		(end 191.79 92.1)
+		(start 195.08 94.84)
+		(end 192.34 92.1)
 		(width 1)
 		(layer "F.Cu")
 		(net "/3V3_MODEM")
@@ -59056,7 +59056,7 @@
 	)
 	(segment
 		(start 196.5 104.25)
-		(end 194.53 102.28)
+		(end 195.08 102.28)
 		(width 1)
 		(layer "F.Cu")
 		(net "/3V3_MODEM")
@@ -59087,8 +59087,8 @@
 		(uuid "d36ee6a6-6b9f-4e5e-b859-4071092616cc")
 	)
 	(segment
-		(start 194.53 102.28)
-		(end 194.53 94.84)
+		(start 195.08 102.28)
+		(end 195.08 94.84)
 		(width 1)
 		(layer "F.Cu")
 		(net "/3V3_MODEM")
@@ -60801,7 +60801,7 @@
 	(segment
 		(start 198.55 68.08)
 		(end 197.41 68.08)
-		(width 1)
+		(width 0.6)
 		(layer "F.Cu")
 		(net "FREQ_FAN")
 		(uuid "854214dc-b383-4346-9e86-16d0d073ba4d")
@@ -60953,7 +60953,7 @@
 	(segment
 		(start 181.485 122.395)
 		(end 181.485 126.38)
-		(width 1.5)
+		(width 0.8)
 		(layer "F.Cu")
 		(net "24V")
 		(uuid "30ed4012-33fd-47aa-81ea-a996984f4150")
@@ -60969,7 +60969,7 @@
 	(segment
 		(start 195.84 69.35)
 		(end 198.55 69.35)
-		(width 1)
+		(width 0.6)
 		(layer "F.Cu")
 		(net "24V")
 		(uuid "479e5357-3d7a-41aa-ac4c-4a9ccb125d81")
@@ -62015,7 +62015,7 @@
 		(uuid "528129cc-2468-48f9-af8d-2ee159f72acd")
 	)
 	(segment
-		(start 166.575 125.625)
+		(start 166.175 125.625)
 		(end 164.71 125.625)
 		(width 0.2)
 		(layer "F.Cu")
@@ -62023,8 +62023,8 @@
 		(uuid "169dd56f-b678-44cd-9f60-2c982a6a22e2")
 	)
 	(segment
-		(start 170.85045 129.90045)
-		(end 166.575 125.625)
+		(start 171.1504 129.9005)
+		(end 166.175 125.625)
 		(width 0.2)
 		(layer "F.Cu")
 		(net "/USB_CC2")
@@ -62056,7 +62056,7 @@
 	)
 	(segment
 		(start 168.852 131.8989)
-		(end 170.85045 129.90045)
+		(end 171.1504 129.9005)
 		(width 0.2)
 		(layer "F.Cu")
 		(net "/USB_CC2")