diff --git a/config/sample-iqex.cfg b/config/sample-iqex.cfg
new file mode 100644
index 000000000..89f5e2521
--- /dev/null
+++ b/config/sample-iqex.cfg
@@ -0,0 +1,348 @@
+# This file contains a configuration snippet for a quad extruder printer
+# with two independent gantries each having two independent tools.
+
+# See docs/Config_Reference.md for a description of parameters.
+# Test config for generic cartesian kinematics with quad independent extruders
+
+[mcu]
+serial: /dev/serial/by-id/usb-Klipper_Klipper_firmware_12345-if00
+
+[mcu auxboard]
+serial: /dev/serial/by-id/usb-Klipper_Klipper_firmware_67890-if11
+
+[carriage carriage_t0]
+axis: x
+position_endstop: 0
+position_max: 300
+homing_speed: 50
+endstop_pin: auxboard:PG6
+
+[dual_carriage carriage_t1]
+primary_carriage: carriage_t0
+safe_distance: 70
+position_endstop: 300
+position_max: 300
+homing_speed: 50
+endstop_pin: auxboard:PG9
+
+[dual_carriage carriage_t2]
+axis: x
+position_endstop: 0
+position_max: 300
+homing_speed: 50
+endstop_pin: auxboard:PG10
+
+[dual_carriage carriage_t3]
+primary_carriage: carriage_t2
+safe_distance: 70
+position_endstop: 300
+position_max: 300
+homing_speed: 50
+endstop_pin: auxboard:PG11
+
+[carriage carriage_gantry0]
+axis: y
+position_endstop: 0
+position_max: 200
+homing_speed: 50
+endstop_pin: PG6
+
+[dual_carriage carriage_gantry1]
+primary_carriage: carriage_gantry0
+safe_distance: 50
+position_endstop: 200
+position_max: 200
+homing_speed: 50
+endstop_pin: PG10
+
+[carriage carriage_z]
+axis: z
+position_endstop: 0.5
+position_max: 100
+endstop_pin: PG12
+
+[stepper stepper_t0_x]
+carriages: carriage_t0
+step_pin: auxboard:PF13
+dir_pin: auxboard:PF12
+enable_pin: !auxboard:PF14
+microsteps: 16
+rotation_distance: 40
+
+[stepper stepper_t1_x]
+carriages: carriage_t1
+step_pin: auxboard:PG0
+dir_pin: auxboard:PG1
+enable_pin: !auxboard:PF15
+microsteps: 16
+rotation_distance: 40
+
+[stepper stepper_t2_x]
+carriages: carriage_t2
+step_pin: auxboard:PF11
+dir_pin: auxboard:PG3
+enable_pin: !auxboard:PG5
+microsteps: 16
+rotation_distance: 40
+
+[stepper stepper_t3_x]
+carriages: carriage_t3
+step_pin: auxboard:PG4
+dir_pin: auxboard:PC1
+enable_pin: !auxboard:PA2
+microsteps: 16
+rotation_distance: 40
+
+[stepper gantry0]
+carriages: carriage_gantry0
+step_pin: PF13
+dir_pin: PF12
+enable_pin: !PF14
+microsteps: 16
+rotation_distance: 40
+
+[stepper gantry1]
+carriages: carriage_gantry1
+step_pin: PF11
+dir_pin: PG3
+enable_pin: !PG5
+microsteps: 16
+rotation_distance: 40
+
+[stepper z0]
+carriages: carriage_z0
+step_pin: PF9
+dir_pin: PF10
+enable_pin: !PG2
+microsteps: 16
+rotation_distance: 8
+
+[extruder]
+step_pin: auxboard:PF9
+dir_pin: auxboard:PF10
+enable_pin: !auxboard:PG2
+heater_pin: auxboard:PA0
+sensor_pin: auxboard:PF4
+microsteps: 16
+rotation_distance: 33.500
+nozzle_diameter: 0.400
+filament_diameter: 1.750
+sensor_type: EPCOS 100K B57560G104F
+control: pid
+pid_Kp: 22.2
+pid_Ki: 1.08
+pid_Kd: 114
+min_temp: 0
+max_temp: 250
+
+[extruder1]
+step_pin: auxboard:PC13
+dir_pin: auxboard:PF0
+enable_pin: !auxboard:PF1
+heater_pin: auxboard:PA3
+sensor_pin: auxboard:PF5
+microsteps: 16
+rotation_distance: 33.5
+nozzle_diameter: 0.400
+filament_diameter: 1.750
+sensor_type: EPCOS 100K B57560G104F
+control: pid
+pid_Kp: 22.2
+pid_Ki: 1.08
+pid_Kd: 114
+min_temp: 0
+max_temp: 250
+
+[extruder2]
+step_pin: auxboard:PE2
+dir_pin: auxboard:PE3
+enable_pin: !auxboard:PD4
+heater_pin: auxboard:PB0
+sensor_pin: auxboard:PF6
+microsteps: 16
+rotation_distance: 33.5
+nozzle_diameter: 0.400
+filament_diameter: 1.750
+sensor_type: EPCOS 100K B57560G104F
+control: pid
+pid_Kp: 22.2
+pid_Ki: 1.08
+pid_Kd: 114
+min_temp: 0
+max_temp: 250
+
+[extruder3]
+step_pin: auxboard:PE6
+dir_pin: auxboard:PA14
+enable_pin: !auxboard:PE0
+heater_pin: auxboard:PB11
+sensor_pin: auxboard:PF7
+microsteps: 16
+rotation_distance: 33.5
+nozzle_diameter: 0.400
+filament_diameter: 1.750
+sensor_type: EPCOS 100K B57560G104F
+control: pid
+pid_Kp: 22.2
+pid_Ki: 1.08
+pid_Kd: 114
+min_temp: 0
+max_temp: 250
+
+[gcode_macro PARK_EXTRUDERS]
+gcode:
+    G90
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1
+    G1 Y{printer.configfile.settings["dual_carriage carriage_gantry1"].position_max} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0
+    G1 Y{printer.configfile.settings["carriage carriage_gantry0"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3
+    G1 X{printer.configfile.settings["dual_carriage carriage_t3"].position_max} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1
+    G1 X{printer.configfile.settings["dual_carriage carriage_t1"].position_max} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2
+    G1 X{printer.configfile.settings["dual_carriage carriage_t2"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0
+    G1 X{printer.configfile.settings["carriage carriage_t0"].position_min} F12000
+
+[gcode_macro T0]
+gcode:
+    PARK_EXTRUDERS
+    ACTIVATE_EXTRUDER EXTRUDER=extruder
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0
+
+[gcode_macro T1]
+gcode:
+    PARK_EXTRUDERS
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder1 MOTION_QUEUE=extruder1
+    ACTIVATE_EXTRUDER EXTRUDER=extruder1
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1
+
+[gcode_macro T2]
+gcode:
+    PARK_EXTRUDERS
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder2 MOTION_QUEUE=extruder2
+    ACTIVATE_EXTRUDER EXTRUDER=extruder2
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2
+
+[gcode_macro T3]
+gcode:
+    PARK_EXTRUDERS
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder3 MOTION_QUEUE=extruder3
+    ACTIVATE_EXTRUDER EXTRUDER=extruder3
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2
+
+[gcode_macro SET_COPY_MODE]
+gcode:
+    G90
+    {% set y_center = 0.5 * (printer.configfile.settings["dual_carriage carriage_gantry1"].position_max + printer.configfile.settings["carriage carriage_gantry0"].position_min) %}
+    {% set x_max = [printer.configfile.settings["dual_carriage carriage_t3"].position_max, printer.configfile.settings["dual_carriage carriage_t1"].position_max]|min %}
+    {% set x_min = [printer.configfile.settings["dual_carriage carriage_t2"].position_min, printer.configfile.settings["carriage carriage_t0"].position_min]|max %}
+    {% set x_center = 0.5 * (x_max + x_min) %}
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0
+    G1 Y{printer.configfile.settings["carriage carriage_gantry0"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1
+    G1 Y{y_center} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2
+    G1 X{printer.configfile.settings["dual_carriage carriage_t2"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0
+    G1 X{printer.configfile.settings["carriage carriage_t0"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3
+    G1 X{x_center} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1
+    G1 X{x_center} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0 MODE=PRIMARY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1 MODE=COPY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2 MODE=COPY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3 MODE=COPY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0 MODE=PRIMARY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1 MODE=COPY
+    ACTIVATE_EXTRUDER EXTRUDER=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder1 MOTION_QUEUE=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder2 MOTION_QUEUE=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder3 MOTION_QUEUE=extruder
+
+[gcode_macro SET_MIRROR_MODE1]
+gcode:
+    G90
+    {% set y_center = 0.5 * (printer.configfile.settings["dual_carriage carriage_gantry1"].position_max + printer.configfile.settings["carriage carriage_gantry0"].position_min) %}
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0
+    G1 Y{printer.configfile.settings["carriage carriage_gantry0"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1
+    G1 Y{y_center} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2
+    G1 X{printer.configfile.settings["dual_carriage carriage_t2"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0
+    G1 X{printer.configfile.settings["carriage carriage_t0"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3
+    G1 X{printer.configfile.settings["dual_carriage carriage_t3"].position_max} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1
+    G1 X{printer.configfile.settings["dual_carriage carriage_t1"].position_max} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0 MODE=PRIMARY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1 MODE=MIRROR
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2 MODE=COPY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3 MODE=MIRROR
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0 MODE=PRIMARY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1 MODE=COPY
+    ACTIVATE_EXTRUDER EXTRUDER=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder1 MOTION_QUEUE=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder2 MOTION_QUEUE=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder3 MOTION_QUEUE=extruder
+
+[gcode_macro SET_MIRROR_MODE2]
+gcode:
+    G90
+    {% set x_max = [printer.configfile.settings["dual_carriage carriage_t3"].position_max, printer.configfile.settings["dual_carriage carriage_t1"].position_max]|min %}
+    {% set x_min = [printer.configfile.settings["dual_carriage carriage_t2"].position_min, printer.configfile.settings["carriage carriage_t0"].position_min]|max %}
+    {% set x_center = 0.5 * (x_max + x_min) %}
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0
+    G1 Y{printer.configfile.settings["carriage carriage_gantry0"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1
+    G1 Y{printer.configfile.settings["dual_carriage carriage_gantry1"].position_max} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2
+    G1 X{printer.configfile.settings["dual_carriage carriage_t2"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0
+    G1 X{printer.configfile.settings["carriage carriage_t0"].position_min} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3
+    G1 X{x_center} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1
+    G1 X{x_center} F12000
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0 MODE=PRIMARY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1 MODE=COPY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2 MODE=COPY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3 MODE=COPY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0 MODE=PRIMARY
+    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1 MODE=MIRROR
+    ACTIVATE_EXTRUDER EXTRUDER=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder1 MOTION_QUEUE=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder2 MOTION_QUEUE=extruder
+    SYNC_EXTRUDER_MOTION EXTRUDER=extruder3 MOTION_QUEUE=extruder
+
+[printer]
+kinematics: generic_cartesian
+max_velocity: 300
+max_accel: 3000
+max_z_velocity: 5
+max_z_accel: 100
+
+## An optional input shaper support
+#[input_shaper]
+## The section is intentionally empty
+#
+#[delayed_gcode init_shaper]
+#initial_duration: 0.1
+#gcode:
+#    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry1
+#    SET_DUAL_CARRIAGE CARRIAGE=carriage_t3
+#    SET_INPUT_SHAPER SHAPER_TYPE_X=<t3_shaper> SHAPER_FREQ_X=<t3_freq> SHAPER_TYPE_Y=<gantry1_shaper> SHAPER_FREQ_Y=<gantry1_freq>
+#    SET_DUAL_CARRIAGE CARRIAGE=carriage_t2
+#    SET_INPUT_SHAPER SHAPER_TYPE_X=<t2_shaper> SHAPER_FREQ_X=<t2_freq> SHAPER_TYPE_Y=<gantry1_shaper> SHAPER_FREQ_Y=<gantry1_freq>
+#    SET_DUAL_CARRIAGE CARRIAGE=carriage_gantry0
+#    SET_DUAL_CARRIAGE CARRIAGE=carriage_t1
+#    SET_INPUT_SHAPER SHAPER_TYPE_X=<t1_shaper> SHAPER_FREQ_X=<t1_freq> SHAPER_TYPE_Y=<gantry0_shaper> SHAPER_FREQ_Y=<gantry0_freq>
+#    SET_DUAL_CARRIAGE CARRIAGE=carriage_t0
+#    SET_INPUT_SHAPER SHAPER_TYPE_X=<t0_shaper> SHAPER_FREQ_X=<t0_freq> SHAPER_TYPE_Y=<gantry0_shaper> SHAPER_FREQ_Y=<gantry0_freq>
diff --git a/docs/Config_Changes.md b/docs/Config_Changes.md
index 6846e034d..4af463243 100644
--- a/docs/Config_Changes.md
+++ b/docs/Config_Changes.md
@@ -8,6 +8,10 @@ All dates in this document are approximate.
 
 ## Changes
 
+20251229: `SET_DUAL_CARRIAGE CARRIAGE=<carriage_name> MODE=<mode>`
+command for modes `COPY` and `MIRROR` now requires that another
+carriage is activated as `PRIMARY` first for the corresponding axis.
+
 20251122: An option `axis` has been added to `[carriage <name>]` sections
 for `generic_cartesian` kinematics, allowing arbitrary names for primary
 carriages. Users are encouraged to explicitly specify `axis` option now.
diff --git a/docs/Config_Reference.md b/docs/Config_Reference.md
index e722a1465..a19f1a4b9 100644
--- a/docs/Config_Reference.md
+++ b/docs/Config_Reference.md
@@ -2445,6 +2445,12 @@ axis:
 #   See the "stepper" section for the definition of the above parameters.
 ```
 
+`[dual_carriage]` is also supported with `generic_cartesian` kinematic,
+in which case it can be thought of as any additional carriage of an axis
+that can be moved independently from the primary `[carriage]` of that axis.
+The main difference between `[carriage]` and `[dual_carriage]` is that
+the latter is not activated by default after the printer startup or
+homing, and must be enabled explicitly via `SET_DUAL_CARRIAGE` command.
 For an example of dual carriage configuration with `generic_cartesian`
 kinematic, see the following configuration
 [sample](../config/example-generic-caretesian.cfg).
@@ -2524,9 +2530,12 @@ Note that `SHAPER_TYPE_Y` and `SHAPER_FREQ_Y` must be the same in both
 commands in this case, since the same motors drive Y axis when either
 of the `carriage_x` and `carriage_u` carriages are active.
 
-It is worth noting that `generic_cartesian` kinematic can support two
-dual carriages for X and Y axes. For reference, see for instance a
-[sample](../config/sample-corexyuv.cfg) of CoreXYUV configuration.
+It is worth noting that `generic_cartesian` kinematic can support more
+than a single `[dual_carriage]`, e.g. dual-gantry setups with one or
+two independent carriages per gantry. For reference, see for instance
+[CoreXYUV](../config/sample-corexyuv.cfg) or
+[IQEX](../config/sample-iqex.cfg) (independent quad extruders)
+printers sample configurations.
 
 ### [extruder_stepper]
 
diff --git a/klippy/kinematics/idex_modes.py b/klippy/kinematics/idex_modes.py
index 4fe6df830..36c32628d 100644
--- a/klippy/kinematics/idex_modes.py
+++ b/klippy/kinematics/idex_modes.py
@@ -244,6 +244,7 @@ class DualCarriages:
     cmd_SET_DUAL_CARRIAGE_help = "Configure the dual carriages mode"
     def cmd_SET_DUAL_CARRIAGE(self, gcmd):
         carriage_str = gcmd.get('CARRIAGE', None)
+        index = None
         if carriage_str is None:
             raise gcmd.error('CARRIAGE must be specified')
         if carriage_str in self.dc_rails:
@@ -265,9 +266,6 @@ class DualCarriages:
         if mode not in self.VALID_MODES:
             raise gcmd.error("Invalid mode=%s specified" % (mode,))
         if mode in [COPY, MIRROR]:
-            if self.primary_mode_dcs[dc_rail.axis] in [None, dc_rail]:
-                raise gcmd.error(
-                        "Must activate another carriage as PRIMARY first")
             curtime = self.printer.get_reactor().monotonic()
             kin = self.printer.lookup_object('toolhead').get_kinematics()
             axis = 'xyz'[dc_rail.axis]
@@ -275,6 +273,12 @@ class DualCarriages:
                 raise gcmd.error(
                         "Axis %s must be homed prior to enabling mode=%s" %
                         (axis.upper(), mode))
+            if index is not None:
+                self.toggle_active_dc_rail(
+                        self.get_dc_rail_wrapper(dc_rail.dual_rail))
+            elif self.primary_mode_dcs[dc_rail.axis] in [None, dc_rail]:
+                raise gcmd.error(
+                        "Must activate another carriage as PRIMARY first")
         self.activate_dc_mode(dc_rail, mode)
     cmd_SAVE_DUAL_CARRIAGE_STATE_help = \
             "Save dual carriages modes and positions"