Steppers stuck with Klipper but work with Marlin
It seems the pinout scheme changed on the Creality board between the versions V4.2.2 and 4.2.8. For example, PB9 &amp; PC2 were inverted between step_pin and dir_pin.
Using the following Klipper config (found here) allows the motors to do their job again.
[stepper_x]
step_pin: PB9
dir_pin: PC2
enable_pin: !PC3
step_distance: .0125
endstop_pin: ^PA5
position_endstop: 0
position_max: 235
homing_speed: 50

[stepper_y]
step_pin: PB7
dir_pin: PB8
enable_pin: !PC3
step_distance: .0125
endstop_pin: ^PA6
position_endstop: 0
position_max: 235
homing_speed: 50

[stepper_z]
step_pin: PB5
dir_pin: !PB6
enable_pin: !PC3
step_distance: .0025
endstop_pin: ^PA7
position_endstop: 0.0
position_max: 250

[extruder]
max_extrude_only_distance: 100.0
step_pin: PB3
dir_pin: PB4
enable_pin: !PC3
step_distance: 0.010752
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: PA1
sensor_type: EPCOS 100K B57560G104F
sensor_pin: PC5
control: pid
# tuned for stock hardware with 200 degree Celsius target
pid_Kp: 21.527
pid_Ki: 1.063
pid_Kd: 108.982
min_temp: 0
max_temp: 250

[heater_bed]
heater_pin: PA2
sensor_type: EPCOS 100K B57560G104F
sensor_pin: PC4
control: pid
# tuned for stock hardware with 50 degree Celsius target
pid_Kp: 54.027
pid_Ki: 0.770
pid_Kd: 948.182
min_temp: 0
max_temp: 130

[fan]
pin: PA0

[mcu]
serial: /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0

[printer]
kinematics: cartesian
max_velocity: 300
max_accel: 3000
max_z_velocity: 5
max_z_accel: 100

[display]
lcd_type: st7920
cs_pin: PB12
sclk_pin: PB13
sid_pin: PB15
encoder_pins: ^PB14, ^PB10
click_pin: ^!PB2 
```