From add866cadc60dcca62d92915c87d4922b76129ed Mon Sep 17 00:00:00 2001
From: stevenrwood <50087820+stevenrwood@users.noreply.github.com>
Date: Wed, 1 Jul 2026 03:36:43 -0700
Subject: [PATCH] gcode: G53 must ignore the active WCS rotation/offset (when
 ROTATION_ENABLE=1)

Only affects builds with ROTATION_ENABLE defined; the offending code is inside
#ifdef ROTATION_ENABLE, so default builds are unaffected.

The rotation-transform block was entered for any axis-word motion without
excluding NonModal_AbsoluteOverride, so G53 (absolute machine override) moves
had the active WCS offset added to the plane axes (and were rotated). Per
RS274/NGC a G53 target is in machine coordinates and must ignore all offsets
and rotation.

Symptom: with a non-zero WCS rotation active (e.g. set by G10 L2 R / G68), G53
drives to the rotated work origin instead of the machine target, false-
triggering a soft-limit alarm when that lands outside the machine envelope.

Guard the transform with `non_modal_command != NonModal_AbsoluteOverride`, and
initialise r_axes.mask = 0 so it stays defined when the block is bypassed.
---
 gcode.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gcode.c b/gcode.c
index bda6249..846a997 100644
--- a/gcode.c
+++ b/gcode.c
@@ -3053,7 +3053,12 @@ status_code_t gc_execute_block (char *block)
 #ifdef ROTATION_ENABLE
                 axes_signals_t r_axes, r_around;
                 uint_fast8_t idx_0, idx_1;
-                if(!gc_parser_flags.jog_motion && (r_axes.mask = (gc_block.modal.g5x_offset.data.rotation == 0.0f ? 0 : (axis_words.mask & (r_around.mask = rotate_axes[gc_block.modal.plane_select].mask))))) {
+                r_axes.mask = 0;   // keep defined when the transform is bypassed (jog / G53)
+                // G53 (absolute machine override) must ignore the active WCS entirely - rotation AND offset. Without
+                // the AbsoluteOverride guard this block adds the g5x offset to the plane axes, so e.g. "G53 G0 X0 Y0"
+                // goes to the work origin instead of machine 0,0 (and false soft-limits when that lands out of travel).
+                // A near-zero garbage rotation (stale NVS after enabling ROTATION_ENABLE) is enough to arm it.
+                if(!gc_parser_flags.jog_motion && gc_block.non_modal_command != NonModal_AbsoluteOverride && (r_axes.mask = (gc_block.modal.g5x_offset.data.rotation == 0.0f ? 0 : (axis_words.mask & (r_around.mask = rotate_axes[gc_block.modal.plane_select].mask))))) {
 
                     if(r_axes.mask != r_around.mask) {
                         point_3d_t pos;