diff --git a/src/libslic3r/calib.cpp b/src/libslic3r/calib.cpp
index ad52476dbd..e7cc7a8932 100644
--- a/src/libslic3r/calib.cpp
+++ b/src/libslic3r/calib.cpp
@@ -676,9 +676,9 @@ CustomGCode::Info CalibPressureAdvancePattern::generate_custom_gcodes(const Dyna
             /* Draw a line at slightly slower accel and speed in order to trick gcode writer to force update acceleration and speed.
              * We do this since several tests may be generated by their own gcode writers which are
              * not aware about their neighbours updating acceleration/speed */
-            gcode << m_writer.set_print_acceleration(accel - 10);
+            gcode << m_writer.set_print_acceleration(std::max<int>(1, accel - 1));
             gcode << move_to(Vec2d(m_starting_point.x(), m_starting_point.y()), m_writer, "Move to starting point", zhop_height, layer_height);
-            gcode << draw_line(m_writer, Vec2d(m_starting_point.x(), m_starting_point.y() + frame_size_y()), line_width(), height_layer(), speed_adjust(speed_perimeter() - 10), "Accel/flow trick line");
+            gcode << draw_line(m_writer, Vec2d(m_starting_point.x(), m_starting_point.y() + frame_size_y()), line_width(), height_layer(), speed_adjust(std::max<int>(1, speed_perimeter() - 1)), "Accel/flow trick line");
             gcode << m_writer.set_print_acceleration(accel);
         }