the original TW firmware:

Supported Features

Part Number: 006-D2606-A0
Locale: 73
Locale ISO code: TW
Sku: 0
Rev: 0A

TTS Phonetics
Junction View
Lane Assist
Speed Limits
Traffic EULA
Photo Nav
ASR
Custom Avoidances
Advanced Detours
Premium Point Addressing
Bluetooth

didnt support english TTS. that's what I want to flash to sg/my firmware.