Critical UI deadlock issue on the Nikon Zf camera with firmware update C version 3.00

Critical UI deadlock issue on the Nikon Zf camera with firmware update C version 3.00 (sent by a reader):

This issue was confirmed by Nikon support in Japan. Under specific settings, the camera loses the ability to display the live view on the rear LCD and cannot exit the i-menu state. Only selfie-mode (LCD rotated 180°) temporarily bypasses the lock. Below are the exact conditions and steps:

Affected settings

• Custom Setting f2: Reassign DISP button to anything other than “DISP”
• Monitor mode: “Auto monitor switch (only when monitor is closed)”
• Monitor usage: Finder priority 2 only

Steps to reproduce

1. Fold the LCD inward (facing the camera body).
2. Without looking into the EVF, press the i-button once → i-menu appears.
3. Open the LCD (but not to the 180° selfie position).

Actual behavior (bug)

• The rear monitor remains stuck, displaying the i-menu.
• Live view never appears (LCD shooting is impossible).
• Half-pressing the shutter, switching AF modes, using other buttons → no exit path.
• Closing the LCD restores EVF shooting, but reopening it re-enters the locked i-menu state.
• The only recovery options are:

1. 1. Restore DISP functionality, or
   2. Initialize the camera.

Expected behavior:

• A half-press of the shutter should close the i-menu and immediately return to live view, as it does when the LCD is still folded.

Additional notes:

• The behavior indicates that the UI state machine has no valid transition from
  (LCD-open + i-menu-on + FinderPriority2 + DISP unassigned).
• The camera enters a “display pipeline deadlock,” with selfie-mode being the only branch
  that forces a full display-mode override.

State diagram (simplified):

+————————-+
| LCD closed |
| i-menu ON |
+———-+————-+
|
| open LCD (not 180°)
v
+——————————-+
| LCD open (normal angle) |
| i-menu ON |
| EXPECTED: shutter half → LV |
| ACTUAL: no exit path ←——–+
+—————+—————+
|
| rotate LCD 180° (selfie mode)
v
+——————————–+
| Selfie mode (LCD 180°) |
| Forced live view override |
+——————————–+

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