diff --git a/keyboards/crkbd/keymaps/christoph-cullmann/keymap.c b/keyboards/crkbd/keymaps/christoph-cullmann/keymap.c
index 0a6cea3..1f19ccc 100644
--- a/keyboards/crkbd/keymaps/christoph-cullmann/keymap.c
+++ b/keyboards/crkbd/keymaps/christoph-cullmann/keymap.c
@@ -7,6 +7,8 @@
 
 char chordal_hold_handedness(keypos_t key)
 {
+    // special handle thumb keys
+    if (key.row == 3 || key.row == 7) return '*';
     return (key.row < MATRIX_ROWS / 2) ? 'L' : 'R';
 }
 
diff --git a/keyboards/ferris/keymaps/christoph-cullmann/keymap.c b/keyboards/ferris/keymaps/christoph-cullmann/keymap.c
index 85c7ef4..d4b8c75 100644
--- a/keyboards/ferris/keymaps/christoph-cullmann/keymap.c
+++ b/keyboards/ferris/keymaps/christoph-cullmann/keymap.c
@@ -7,6 +7,8 @@
 
 char chordal_hold_handedness(keypos_t key)
 {
+    // special handle thumb keys
+    if (key.row == 3 || key.row == 7) return '*';
     return (key.row < MATRIX_ROWS / 2) ? 'L' : 'R';
 }
 
diff --git a/keyboards/planck/keymaps/christoph-cullmann/keymap.c b/keyboards/planck/keymaps/christoph-cullmann/keymap.c
index c44517f..d64381e 100644
--- a/keyboards/planck/keymaps/christoph-cullmann/keymap.c
+++ b/keyboards/planck/keymaps/christoph-cullmann/keymap.c
@@ -7,7 +7,9 @@
 
 char chordal_hold_handedness(keypos_t key)
 {
-    return ((key.row < 3) || (key.row == 3 && key.col < 3) || (key.row == 7 && key.col > 2)) ? 'L' : 'R';
+    // special handle thumb keys
+    if (key.row == 3 || key.row == 7) return '*';
+    return (key.row < MATRIX_ROWS / 2) ? 'L' : 'R';
 }
 
 // layout helper macro, we just use 42 keys