ie D2785 --> D8888 or any number you want to try .:)
You have to point where is TTS voice in fw_all., so I seek for "Jill" because it's a TTS voice.
You should replace other name at start point of original TTS voice that be replaced.
You can compare where is the point should be replaced by picture in post No.1
Rem :: Don't worry if you use original boot.bin
Your device will always boot up even you make a mistake in fw_all
If you get a rebooting problem ., just flash nuvi with RGN from original firmware.
You can make a rgn by RGN_Tool.
Open original firmware and save to a rgn file., That's it. !! :)
After that your nuvi will alive as normal again., I promise !
Now I try to modified 765 TW swv 3.10 to use Thai jcv file.
My 7x5 get rebooting in many times because of my mistake.
I just recovered by rgn .,
So., you can try ., don't worry.