rbutil: try to detect position of tts executeables without opening the config window.
tree0e0f265af4a2d90cc0d7a4c2e1bd3f44ba5e201b
drwxr-xr-x - apps
drwxr-xr-x - backdrops
drwxr-xr-x - bootloader
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drwxr-xr-x - firmware
drwxr-xr-x - flash
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