Family BASIC Keyboard detection fails in Lode Runner

[TakuikaNinja]

Describe the bug
The Family BASIC Keyboard fails to be detected by Lode Runner. The game only allows cassette tape I/O (via the Family BASIC Data Recorder) if the keyboard is connected.

To Reproduce
Steps to reproduce the behavior:

1. Open Lode Runner (only checked on Japanese version so far)
2. Connect & enable Family BASIC Keyboard in the input settings
3. Select "EDIT" on title screen
4. Press Select, nothing will happen

Expected behavior
The game should detect the Family BASIC Keyboard and display a menu screen to save level data to the Family BASIC Data Recorder. This works correctly in Mesen2.

(please complete the following information):

• EndeavourOS on 6.13.2-zen1-1-zen
• FCEUX Version 2.6.6 (QT)

Additional context
The NESdev Wiki has documentation regarding the detection method used by Lode Runner: https://www.nesdev.org/wiki/Family_BASIC_Keyboard#Keyboard_detection_in_other_games

[decrazyo]

This issue also impacts my homebrew project, NES86.
NES86 uses the same method as Lode Runner to detect the presence of a Family BASIC Keyboard at startup.