diff --git a/grbl/gcode.c b/grbl/gcode.c
index 3778ee48a..810fc6ee5 100644
--- a/grbl/gcode.c
+++ b/grbl/gcode.c
@@ -528,6 +528,7 @@ uint8_t gc_execute_line(char *line)
       else { coord_select = gc_block.modal.coord_select; } // Index P0 as the active coordinate system
       
       // NOTE: Store parameter data in IJK values. By rule, they are not in use with this command.
+      // FIXME: Instead of IJK, we'd better use: float vector[N_AXIS]; // [DG]
       if (!settings_read_coord_data(coord_select,gc_block.values.ijk)) { FAIL(STATUS_SETTING_READ_FAIL); } // [EEPROM read fail]
 
       // Pre-calculate the coordinate data changes.
diff --git a/grbl/gcode.h b/grbl/gcode.h
index 0215c8861..897bca228 100644
--- a/grbl/gcode.h
+++ b/grbl/gcode.h
@@ -195,7 +195,7 @@ typedef struct {
 
 typedef struct {
   float f;         // Feed
-  float ijk[3];    // I,J,K Axis arc offsets
+  float ijk[N_AXIS];    // I,J,K Axis arc offsets
   uint8_t l;       // G10 or canned cycles parameters
   int32_t n;       // Line number
   float p;         // G10 or dwell parameters