diff --git a/4.18/wacom_wac.c b/4.18/wacom_wac.c
index d89f9a72..29baf481 100644
--- a/4.18/wacom_wac.c
+++ b/4.18/wacom_wac.c
@@ -1373,9 +1373,9 @@ static void wacom_intuos_pro2_bt_pen(struct wacom_wac *wacom)
 					rotation -= 1800;
 
 				input_report_abs(pen_input, ABS_TILT_X,
-						 (char)frame[7]);
+						 (signed char)frame[7]);
 				input_report_abs(pen_input, ABS_TILT_Y,
-						 (char)frame[8]);
+						 (signed char)frame[8]);
 				input_report_abs(pen_input, ABS_Z, rotation);
 				input_report_abs(pen_input, ABS_WHEEL,
 						 get_unaligned_le16(&frame[11]));