Thank you for the guide. Successfully installed the English version. The interface for dashcam changed to English, voice is in English and dashcam can accept instruction in English too! e.g. Take phote and record video (any other voice instructions?).
What I did was:
1. Download the English firmware
Thank you ttleng for the link

https://mega.nz/#!jcBhAYZI!XlYL4o9a...j7IOjcnTY9FtJjM

2. Extract to phone or PC. Extract the zip file. Take note the file needed is "UPDATE" file and not the full name file
3. Format the memory card using dashcam interface or apps
4. Shutdown the dashcam. Hold the long button at below
5. Using the memory card reader, copy "update" file directly into memory card root (don't put into any folder)
6. Place back memory card into dashcam and power on using the most right button + long below button. Release the long button once the dashcam start and release right button once the dashcam start updating the new file
7. The dashcam will change to English afterwards.