diff --git a/CHANGELOG.md b/CHANGELOG.md
index d009f0f77..574fadcf1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ All notable changes to Bambuddy will be documented in this file.
 - **Spoolman Creates Duplicate Spools on Startup** ([#295](https://github.com/maziggy/bambuddy/pull/295)) — Each AMS tray independently fetched all spools from Spoolman, causing redundant API calls and duplicate spool creation with large databases (300+ spools). Now fetches spools once and reuses cached data across all tray operations. Added retry logic (3 attempts, 500ms delay) with connection recreation for transient network errors.
 - **Filament Usage Charts Inflated by Quantity Multiplier** ([#229](https://github.com/maziggy/bambuddy/issues/229)) — Daily, weekly, and filament-type charts were multiplying `filament_used_grams` by print quantity, even though the value already represents the total for the entire job. A 26-object print using 126g was counted as 3,276g. Removed the erroneous multiplier from three aggregations in `FilamentTrends.tsx`.
 - **Energy Cost Shows 0.00 in "Total Consumption" Mode** ([#284](https://github.com/maziggy/bambuddy/issues/284)) — Statistics Quick Stats showed 0.00 energy cost when Energy Display Mode was set to "Total Consumption" with Home Assistant smart plugs. The `homeassistant_service` was not configured with HA URL/token before querying plug energy data, causing it to silently return nothing.
+- **H2D Pro Prints Fail at ~75% With Extrusion Motor Overload** ([#245](https://github.com/maziggy/bambuddy/issues/245)) — H2D Pro firmware interprets `use_ams: 1` (integer) as a nozzle index, routing filament to the deputy nozzle instead of the main nozzle. Bambu Studio sends `use_ams: true` (boolean) while using integers for other fields. Fixed by keeping `use_ams` as boolean for all printers including H2D series.
 
 ### Documentation
 - **Proxy Mode Security Warning** — Added FTP data channel security warning to wiki, README, and website. Bambu Studio does not encrypt the FTP data channel despite negotiating PROT P; MQTT and FTP control channels are fully TLS-encrypted. VPN (Tailscale/WireGuard) recommended for full data encryption.
diff --git a/backend/app/services/bambu_mqtt.py b/backend/app/services/bambu_mqtt.py
index 89cf09d69..45a3c3937 100644
--- a/backend/app/services/bambu_mqtt.py
+++ b/backend/app/services/bambu_mqtt.py
@@ -2049,8 +2049,10 @@ class BambuMQTTClient:
                         slot_id = tray_id % 4
                         ams_mapping2.append({"ams_id": ams_id, "slot_id": slot_id})
 
-            # H2D series requires integer values (0/1) for boolean fields
-            # Other printers (X1C, P1S, A1, etc.) require actual booleans
+            # H2D series requires integer values (0/1) for calibration/leveling fields
+            # but use_ams MUST remain boolean — H2D Pro firmware interprets integer
+            # values as nozzle index (1 = deputy nozzle), causing wrong extruder routing
+            # Other printers (X1C, P1S, A1, etc.) require actual booleans for all fields
             is_h2d = self.model and self.model.upper().strip() in ("H2D", "H2D PRO", "H2DPRO", "H2C", "H2S")
 
             command = {
@@ -2068,7 +2070,7 @@ class BambuMQTTClient:
                     "flow_cali": (1 if flow_cali else 0) if is_h2d else flow_cali,
                     "vibration_cali": (1 if vibration_cali else 0) if is_h2d else vibration_cali,
                     "layer_inspect": (1 if layer_inspect else 0) if is_h2d else layer_inspect,
-                    "use_ams": (1 if use_ams else 0) if is_h2d else use_ams,
+                    "use_ams": use_ams,
                     "cfg": "0",
                     "extrude_cali_flag": 0,
                     "extrude_cali_manual_mode": 0,
@@ -2082,7 +2084,10 @@ class BambuMQTTClient:
             }
 
             if is_h2d:
-                logger.info("[%s] H2D series detected: using integer format for boolean fields", self.serial_number)
+                logger.info(
+                    "[%s] H2D series detected: using integer format for calibration fields (use_ams stays boolean)",
+                    self.serial_number,
+                )
 
             # P2S-specific parameter adjustments
             # P2S printer doesn't support vibration calibration like X1/P1 series